平狄克微观经济学答案
平狄克《微观经济学》课后答案 18
CHAPTER 18EXTERNALITIES AND PUBLIC GOODSThis chapter extends the discussion of market failure begun in Chapter 17. To avoid over-emphasis on definitions, stress the main theme of the chapter: the characteristics of some goods lead to situations where price is not equal to marginal cost. Rely on the discussion of market power (Chapter 10) as an example of market failure. Also, point out with each case that government intervention might not be required if property rights can be defined and transaction costs are small (Section 18.3). The first four sections present positive and negative externalities and solutions to market failure. The last two sections discuss public goods and public choice.The consumption of many goods involves the creation of externalities. Stress the divergence between social and private costs. Exercise (5) presents the classic beekeeper/apple-orchard problem, originally popularized in Meade, “External Economies and Diseconomies in a Competitive Situation,” Economic Journal (March 1952). Empirical research on this example has shown that beekeepers and orchard owners have solved many of their problems: see Cheung, “The Fable of the Bees: An Economic Investigation,” Journal of Law and Economics (April 1973).Solutions to the problems of externalities are presented in Sections 18.2 and 18.3. Section 18.2, in particular, discusses emission standards, fees, and transferable permits. Example 18.1 and Exercise (3) are simple applications of these concepts.One of the main themes of the law and economics literature since 1969 is the application of Coase’s insight on the assignment of property rights. The original article is clear and can be understood by students. Stress the problems posed by transactions costs. For a lively debate, ask students whether non-smokers should be granted the right to smokeless air in public places (see Exercise (4)). For an extended discussion of the Coase Theorem at the undergraduate level, see Polinsky, Chapters 3-6, An Introduction to Law & Economics (Little, Brown & Co., 1983).The section on common property resources emphasizes the distinction between private and social marginal costs. Example 18.5 calculates the social cost of unlimited access to common property, and the information provided is used in Exercise (7). Exercise (8) provides an extended example of managing common property.The last two sections focus on public goods and private choice. Point out the similarities and differences between public goods and other activities with externalities. Since students confuse nonrival and nonexclusive goods, create a table similar to the following and give examples to fill in the cells:The next stumbling block for students is achieving an understanding of why we add individual demand curves vertically rather than horizontally. Exercise (6) compares vertical and horizontal summation of individual demand.The presentation of public choice is a limited introduction to the subject, but you can easily expand on this material. A logical extension of this chapter is an introduction to cost-benefit analysis. For applications of this analysis, see Part III, “Empirical Analysis of Policies and Programs,” in Haveman and Margolis (eds.), Public Expenditure and Policy Analysis (Houghton Mifflin, 1983).1. Which of the following describes an externality and which does not? Explain the difference.a. A policy of restricted coffee exports in Brazil causes the U.S. price of coffee to rise,which in turn also causes the price of tea to increase.Externalities cause market inefficiencies by preventing prices from conveying accurateinformation. A policy of restricting coffee exports in Brazil causes the U.S. price ofcoffee to rise, because supply is reduced. As the price of coffee rises, consumers switchto tea, thereby increasing the demand for tea, and hence, increasing the price of tea.These are market effects, not externalities.b. An advertising blimp distracts a motorist who then hits a telephone pole.An advertising blimp is producing information by announcing the availability of somegood or service. However, its method of supplying this information can be distractingfor some consumers, especially those consumers who happen to be driving neartelephone poles. The blimp is creating a negative externality that influences thedrivers’ safety. Since the price charged by the advertising firm does not incorporate theexternality of distracting drivers, too much of this type of advertising is produced fromthe point of view of society as a whole.2. Compare and contrast the following three mechanisms for treating pollution externalities when the costs and benefits of abatement are uncertain: (a) an emissions fee, (b) an emissions standard, and (c) a system of transferable emissions permits.Since pollution is not reflected in the marginal cost of production, its emission createsan externality. Three policy tools can be used to reduce pollution: an emissions fee, anemissions standard, and a system of transferable permits. The choice between a feeand a standard will depend on the marginal cost and marginal benefit of reducingpollution. If small changes in abatement yield large benefits while adding little to cost,the cost of not reducing emissions is high. Thus, standards should be used. However, ifsmall changes in abatement yield little benefit while adding greatly to cost, the cost ofreducing emissions is high. Thus, fees should be used.A system of transferable emissions permits combines the features of fees and standardsto reduce pollution. Under this system, a standard is set and fees are used to transferpermits to the firm that values them the most (i.e., a firm with high abatement costs).However, the total number of permits can be incorrectly chosen. Too few permits willcreate excess demand, increasing price and inefficiently diverting resources to ownersof the permits. Typically, pollution control agencies implement one of threemechanisms, measure the results, reassess the success of their choice, then reset newlevels of fees or standards or select a new policy tool.3. When do externalities require government intervention, and when is such intervention unlikely to be necessary?Economic efficiency can be achieved without government intervention when theexternality affects a small number of people and when property rights are wellspecified. When the number of parties is small, the cost of negotiating an agreementamong the parties is small. Further, the amount of required information (i.e., the costsof and benefits to each party) is small. When property rights are not well specified,uncertainty regarding costs and benefits increases and efficient choices might not bemade. The costs of coming to an agreement, including the cost of delaying such anagreement, could be greater than the cost of government intervention, including theexpected cost of choosing the wrong policy instrument.4. An emissions fee is paid to the government, whereas an injurer who is sued and is held liable pays damages directly to the party harmed by an externality. What differences in the behavior of victims might you expect to arise under these two arrangements?When the price of an activity that generates an externality reflects social costs, anefficient level of the activity is maintained. The producer of the externality reduces (fornegative externalities) or increases (for positive externalities) activity away from(towards) efficient levels. If those who suffer from the externality are not compensated,they find that their marginal cost is higher (for negative externalities) or lower (forpositive externalities), in contrast to the situation in which they would be compensated.5. Why does free access to a common property resource generate an inefficient outcome?Free access to a resource means that the marginal cost to the user is less than the socialcost. The use of a common property resource by a person or firm excludes others fromusing it. For example, the use of water by one consumer restricts its use by another.Because private marginal cost is below social marginal cost, too much of the resource isconsumed by the individual user, creating an inefficient outcome.6. Public goods are both nonrival and nonexclusive. Explain each of these terms and state clearly how they differ from each other.A good is nonrival if, for any level of production, the marginal cost of providing the goodto an additional consumer is zero (although the production cost of an additional unitcould be greater than zero). A good is nonexclusive if it is impossible or very expensiveto exclude individuals from consuming it. Public goods are nonrival and nonexclusive.Commodities can be (1) exclusive and rival, (2) exclusive and nonrival, (3) nonexclusiveand rival, or (4) nonexclusive and nonrival. Most of the commodities discussed in thetext to this point have been of the first type. In this chapter, we focus on commodities ofthe last type.Nonrival refers to the production of a good or service for one more customer. It usuallyinvolves a production process with high fixed costs, such as the cost of building ahighway or lighthouse. (Remember that fixed cost depends on the period underconsideration: the cost of lighting the lamp at the lighthouse can vary over time, butdoes not vary with the number of consumers.) Nonexclusive refers to exchange, wherethe cost of charging consumers is prohibitive. Incurring the cost of identifyingconsumers and collecting from them would result in losses. Some economists focus onthe nonexclusion property of public goods because it is this characteristic that poses themost significant problems for efficient provision.7. Public television is funded in part by private donations, even though anyone with a television set can watch for free. Can you explain this phenomenon in light of the free rider problem?The free-rider problem refers to the difficulty of excluding persons from consuming anonexclusive commodity. Non-paying consumers can “free-ride” on commoditiesprovided by paying customers. Public television is funded in part by contributions.Some viewers contribute, but most watch without paying, hoping that someone else willpay so they will not. To combat this problem these stations (1) ask consumers to assesstheir true willingness to pay, then (2) ask consumers to contribute up to this amount,and (3) attempt to make everyone else feel guilty for free-riding.8. Explain why the median voter outcome need not be efficient when majority rule voting determines the level of public spending.The median voter is the citizen with the middle preference: half the voting population ismore strongly in favor of the issue and half is more strongly opposed to the issue.Under majority-rule voting, where each citizen’s vote is weighted equally, the preferredspending level on public-goods provision of the median voter will win an electionagainst any other alternative.However, majority rule is not necessarily efficient, because it weights each citizen’spreferences equally. For an efficient outcome, we would need a system that measuresand aggregates the willingness to pay of those citizens consuming the public good.Majority rule is not this system. However, as we have seen in previous chapters,majority rule is equitable in the sense that all citizens are treated equally. Thus, weagain find a trade-off between equity and efficiency.1. A number of firms located in the western portion of a town after single-family residences took up the eastern portion. Each firm produces the same product and, in the process, emits noxious fumes that adversely affect the residents of the community.a. Why is there an externality created by the firms?Noxious fumes created by firms enter the utility function of residents. We can assumethat the fumes decrease the utility of the residents (i.e., they are a negative externality)and lower property values.b. Do you think that private bargaining can resolve the problem with the externality?Explain.If the residents anticipated the location of the firms, housing prices should reflect thedisutility of the fumes; the externality would have been internalized by the housingmarket in housing prices. If the noxious fumes were not anticipated, privatebargaining could resolve the problem of the externality only if there are a relativelysmall number of parties (both firms and families) and property rights are well specified.Private bargaining would rely on each family’s willingness to pay for air quality, buttruthful revelation might not be possible. All this will be complicated by theadaptability of the production technology known to the firms and the employmentrelations between the firms and families. It is unlikely that private bargaining willresolve the problem.c. How might the community determine the efficient level of air quality?The community could determine the economically efficient level of air quality byaggregating the families’ willingne ss to pay and equating it with the marginal cost ofpollution reduction. Both steps involve the acquisition of truthful information.2. A computer programmer lobbies against copyrighting software. He argues that everyone should benefit from innovative programs written for personal computers and that exposure to a wide variety of computer programs will inspire young programmers to create even more innovative programs. Considering the marginal social benefits possibly gained by his proposal, do you agree with the programmer’s position?Computer software as information is a classic example of a public good. Since it can becostlessly copied, the marginal cost of providing software to an additional user is nearzero. Therefore, software is nonrival. (The fixed costs of creating software are high, butthe variable costs are low.) Furthermore, it is expensive to exclude consumers fromcopying and using software because copy protection schemes are available only at highcost or high inconvenience to users. Therefore, software is also nonexclusive. As bothnonrival and nonexclusive, computer software suffers the problems of public goodsprovision: the presence of free-riders makes it difficult or impossible for markets toprovide the efficient level of software. Rather than regulating this market directly, thelegal system guarantees property rights to the creators of software. If copyrightprotection were not enforced, it is likely that the software market would collapse.Therefore, we do not agree with the computer programmer.3. Four firms located at different points on a river dump various quantities of effluent into it. The effluent adversely affects the quality of swimming for homeowners who live downstream. These people can build swimming pools to avoid swimming in the river, and firms can purchase filters that eliminate harmful chemicals in the material that is dumped in the river. As a policy advisor for a regional planning organization, how would you compare and contrast the following options for dealing with the harmful effect of the effluent:a. An equal-rate effluent fee on firms located on the river.First, one needs to know the value to homeowners of swimming in the river. Thisinformation can be difficult to obtain, because homeowners will have an incentive tooverstate this value. As an upper boundary, if there are no considerations other thanswimming, one could use the cost of building swimming pools, either a pool for eachhomeowner or a public pool for all homeowners. Next, one needs to know the marginalcost of abatement. If the abatement technology is well understood, this informationshould be readily obtainable. If the abatement technology is not understood, anestimate based on the firms’ knowledge must be used.The choice of a policy tool will depend on the marginal benefits and costs of abatement.If firms are charged an equal-rate effluent fee, the firms will reduce effluents to thepoint where the marginal cost of abatement is equal to the fee. If this reduction is nothigh enough to permit swimming, the fee could be increased. Alternatively, revenuefrom the fees could be to provide swimming facilities, reducing the need for effluentreduction.b. An equal standard per firm on the level of effluent each firm can dump.Standards will be efficient only if the policy maker has complete information regardingthe marginal costs and benefits of abatement. Moreover, the standard will notencourage firms to reduce effluents further when new filtering technologies becomeavailable.c. A transferable effluent permit system, in which the aggregate level of effluent isfixed and all firms receive identical permits.A transferable effluent permit system requires the policy maker to determine theefficient effluent standard. Once the permits are distributed and a market develops,firms with a higher cost of abatement will purchase permits from firms with lowerabatement costs. However, unless permits are sold initially, rather than merelydistributed, no revenue will be generated for the regional organization.4. Recent social trends point to growing intolerance of smoking in public areas. Many people point out the negative effects of “second hand” smoke. If you are a smoker and you wish to continue smoking despite tougher anti smoking laws, describe the effect of the following legislative proposals on your behavior. As a result of these programs, do you, the individual smoker, benefit? Does society benefit as a whole?Since smoking in public areas is similar to polluting the air, the programs proposedhere are similar to those examined for air pollution. A bill to lower tar and nicotinelevels is similar to an emissions standard, and a tax on cigarettes is similar to anemissions fee. Requiring a smoking permit is similar to a system of emissions permits,assuming that the permits would not be transferable. The individual smoker in all ofthese programs is being forced to internalize the externality of “second-hand” smokeand will be worse off. Society will be better off if the benefits of a particular proposaloutweigh the cost of implementing that proposal. Unfortunately, the benefits ofreducing second-hand smoke are uncertain, and assessing those benefits is costly.a. A bill is proposed that would lower tar and nicotine levels in all cigarettes.The smoker will most likely try to maintain a constant level of consumption of nicotine,and will increase his or her consumption of cigarettes. Society may not benefit fromthis plan if the total amount of tar and nicotine released into the air is the same.b. A tax is levied on each pack of cigarettes sold.Smokers might turn to cigars, pipes, or might start rolling their own cigarettes. Theextent of the effect of a tax on cigarette consumption depends on the elasticity ofdemand for cigarettes. Again, it is questionable whether society will benefit.c. Smokers would be required to carry smoking permits at all times. These permitswould be sold by the government.Smoking permits would effectively transfer property rights to clean air from smokers tonon-smokers. The main obstacle to society benefiting from such a proposal would bethe high cost of enforcing a smoking permits system.5. A beekeeper lives adjacent to an apple orchard. The orchard owner benefits from thebees because each hive pollinates about one acre of apple trees. The orchard owner pays nothing for this service, however, because the bees come to the orchard without his having to do anything. There are not enough bees to pollinate the entire orchard, and the orchard owner must complete the pollination by artificial means, at a cost of $10 per acre of trees.Beekeeping has a marginal cost of MC = 10 + 2Q, where Q is the number of beehives.Each hive yields $20 worth of honey.a. How many beehives will the beekeeper maintain?The beekeeper maintains the number of hives that maximizes profits, when marginalrevenue is equal to marginal cost. With a constant marginal revenue of $20 (there is noinformation that would lead us to believe that the beekeeper has any market power)and a marginal cost of 10 + 2Q:20 = 10 + 2Q, or Q = 5.b. Is this the economically efficient number of hives?If there are too few bees to pollinate the orchard, the farmer must pay $10 per acre forartificial pollination. Thus, the farmer would be willing to pay up to $10 to thebeekeeper to maintain each additional hive. So, the marginal social benefit, MSB, ofeach additional hive is $30, which is greater than the marginal private benefit of $20.Assuming that the private marginal cost is equal to the social marginal cost, we setMSB = MC to determine the efficient number of hives:30 = 10 + 2Q, or Q = 10.Therefore, the beekeeper’s private choice of Q = 5 is not the socially efficient number ofhives.c. What changes would lead to the more efficient operation?The most radical change that would lead to more efficient operations would be themerger of the farmer’s business with the beekeeper’s business. This merger wouldinternalize the positive externality of bee pollination. Short of a merger, the farmerand beekeeper should enter into a contract for pollination services.7. Reconsider the common resource problem as given by Example 18.5. Suppose that crawfish popularity continues to increase, and that the demand curve shifts from C = 0.401 - 0.0064F to C = 0.50 - 0.0064F. How does this shift in demand affect the actual crawfish catch, the efficient catch, and the social cost of common access? (Hint: Use the marginal social cost and private cost curves given in the example.)The relevant information is now the following:Demand: C = 0.50 - 0.0064FMSC: C = -5.645 + 0.6509F.With an increase in demand, the demand curve for crawfish shifts upward, intersectingthe price axis at $0.50. The private cost curve has a positive slope, so additional effortmust be made to increase the catch. Since the social cost curve has a positive slope, thesocially efficient catch also increases. We may determine the socially efficient catch bysolving the following two equations simultaneously:0.50 - 0.0064F = -5.645 + 0.6509F, or F* = 9.35.To determine the price that consumers are willing to pay for this quantity, substituteF* into the equation for marginal social cost and solve for C:C = -5.645 + (0.6509)(9.35), or C = $0.44.Next, find the actual level of production by solving these equations simultaneously:Demand: C = 0.50 - 0.0064FMPC: C = -0.357 + 0.0573F0.50 - 0.0064F = -0.357 + 0.0573F, or F** = 13.45.To determine the price that consumers are willing to pay for this quantity, substituteF** into the equation for marginal private cost and solve for C:C = -0.357 + (0.0573)(13.45), or C = $0.41.Notice that the marginal social cost of producing 13.45 units isMSC = -5.645 +(0.6509)(13.45) = $3.11.With the increase in demand, the social cost is the area of a triangle with a base of 4.1million pounds (13.45 - 9.35) and a height of $2.70 ($3.11 - 0.41), or $5,535,000 morethan the social cost of the original demand.8. The Georges Bank, a highly productive fishing area off New England, can be divided into two zones in terms of fish population. Zone 1 has the higher population per square mile but is subject to severe diminishing returns to fishing effort. The daily fish catch (in tons) in Zone 1 isF 1 = 200(X1) - 2(X1) 2where X1is the number of boats fishing there. Zone 2 has fewer fish per mile but is larger, and diminishing returns are less of a problem. Its daily fish catch isF 2 = 100(X2) - (X2) 2where X2is the number of boats fishing in Zone 2. The marginal fish catch MFC in each zone can be represented asMFC1 = 200 - 4(X1) MFC2= 100 - 2(X2).There are 100 boats now licensed by the U.S. government to fish in these two zones. The fish are sold at $100 per ton. The total cost (capital and operating) per boat is constant at $1,000 per day. Answer the following questions about this situation.a. If the boats are allowed to fish where they want, with no government restriction,how many will fish in each zone? What will be the gross value of the catch?Without restrictions, the boats will divide themselves so that the average catch (AF 1and AF 2) for each boat is equal in each zone. (If the average catch in one zone is greaterthan in the other, boats will leave the zone with the lower catch for the zone with thehigher catch.) We solve the following set of equations:AF 1 = AF 2 and X 1 + X 2 = 100 where 11121120022002AF X X X X =-=- and 222222100100AF X X X X =-=-. Therefore, AF 1 = AF 2 implies200 - 2X 1 = 100 - X 2,200 - 2(100 - X 2) = 100 - X 2, or X 21003= and 320031001001=⎪⎭⎫ ⎝⎛-=X . Find the gross catch by substituting the value of X 1 and X 2 into the catch equations:()(),,,,F 444488983331332002320020021=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= and ().,,,F 2222111133333100310010022=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= The total catch is F 1 + F 2 = 6,666. At the price of $100 per ton, the value of the catch is$666,600. The average catch for each of the 100 boats in the fishing fleet is 66.66 tons.To determine the profit per boat, subtract total cost from total revenue:π = (100)(66.66) - 1,000, or π = $5,666.Total profit for the fleet is $566,000.b. If the U.S. government can restrict the boats, how many should be allocated to eachzone? What will the gross value of the catch be? Assume the total number of boats remains at 100.Assume that the government wishes to maximize the net social value of the fish catch,i.e., the difference between the total social benefit and the total social cost. Thegovernment equates the marginal fish catch in both zones, subject to the restrictionthat the number of boats equals 100:MFC 1 = MFC 2 and X 1 + X 2 = 100,MFC 1 = 200 - 4X 1 and MFC 2 = 100 - 2X 2.Setting MFC 1 = MFC 2 implies:200 - 4X 1 = 100 - 2X 2, or 200 - 4(100 - X 2) = 100 - 2X 2, or X 2 = 50 andX 1 = 100 - 50 = 50.Find the gross catch by substituting X 1 and X 2 into the catch equations:F 1 = (200)(50) - (2)(502) = 10,000 - 5,000 = 5,000 andChapter 18: Externalities and Public Goods242 F 2 = (100)(50) - 502 = 5,000 - 2,500 = 2,500.The total catch is equal to F 1 + F 2 = 7,500. At the market price of $100 per ton, thevalue of the catch is $750,000. Total profit is $650,000. Notice that the profits are notevenly divided between boats in the two zones. The average catch in Zone A is 100 tonsper boat, while the average catch in Zone B is 50 tons per boat. Therefore, fishing inZone A yields a higher profit for the individual owner of the boat.c. If additional fishermen want to buy boats and join the fishing fleet, should agovernment wishing to maximize the net value of the fish catch grant them licenses to do so? Why or why not?To answer this question, first determine the profit-maximizing number of boats in eachzone. Profits in Zone A areππA A X X X X X =--=-1002002100019000200112112b g e j,,, or . To determine the change in profit with a change in X 1 take the first derivative of theprofit function with respect to X 1:d dX X A π1119000400=-,. To determine the profit-maximizing level of output, setd dX A π1equal to zero and solve for X 1:19,000 - 400X 1 = 0, or X 1 = 47.5.Substituting X 1 into the profit equation for Zone A gives: ()()()()()()()()250,451$5.47000,15.4725.472001002=--=A π.For Zone B follow a similar procedure. Profits in Zone B areππB B X X X X X =--=-100100100090002002222222b g e j,,, or . Taking the derivative of the profit function with respect to X 2 givesd X B π229000200=-,. Setting d B π2equal to zero to find the profit-maximizing level of output gives 9,000 - 200X 2 = 0, or X 2 = 45.Substituting X 2 into the profit equation for Zone B gives:πB = (100)((100)(45) - 452) - (1,000)(45) = $202,500.Total profit from both zones is $653,750, with 47.5 boats in Zone A and 45 boats in ZoneB. Because each additional boat above 92.5 decreases total profit, the governmentshould not grant any more licenses.。
平狄克第八版课后答案
平狄克第八版课后答案【篇一：平狄克微观经济学课后习题答案-第7-8 章】> 1. 显性成本2. 她自己做其他事时会得到的最高收入3. 多用资本,少用工人4. 完全竞争价格给定, 即斜率不变5. 不意味6. 意味着递增7. avcac mc 递增mc=avc 最低点mc=ac 最低点1.1 形9 . 长期扩展线为把等产量线簇上斜率相同点连起来,此时它改变了斜率10 .规模经济基础是内在经济,针对一种产品范围经济基础是同时生产高度相关的产品.练习题1.avc=1000 ac=1000+1000/q非常大,最后为10002. 不对,除非工人只可以在这里找到工作3. 见书后4. 见书后5. 见书后6. 每个均衡点斜率更小7. 不同意,应按不同时段定价,如不可,则同意8. 见书后9.tc=120000+3000(q/40)+2000ac=75+122000/qmc=75ac 随q 减小2 个劳动组,1600 元1/4, 更大的生产能力11.190 万元53 元53 元19 元第七章附录练习题1 、我们考查规模报酬时可由f( ak，al)与af( k，l)之间的关系判断当f( ak，al) af( k，l),表明是规模报酬递增；当f( ak，al) =af( k，l),表明是规模报酬不变；当f( ak，al) af( k，l),表明是规模报酬递减；( a)规模报酬递增；( b)规模报酬不变；( c)规模报酬递增。
2 、根据已知条件，资本价格r=30 ，设劳动价格为w，则成本函数c=30k+ wl联立(1) ，(2)，(3)可得k=(w/3) 1/2 ,l=(300/w) 1/2 ,此时成本最小，代入成本函数c=30k+ wl ，得c=2 ( 300w ) 1/2联立(1) ，(2)，(3)可得k/l=3/4 ,此时成本最小，即生产既定产出的成本最小化的资本和劳动的组合为资本/劳动=3/4。
4、( a)已知q=10k0.8(l-40)0.2 ,得mpl=2(k/ (l-40))0.8 , mpk=8( (l-40) / k)0.2 ,在最小成本点有：mpl/ mpk=w/r即2(k/ (l-40))0.8/8( (l-40) / k)0.2=w/r ，k/( l-40) =4 w/r ，l-40=kr/4w ，0.80.20.2q=10k(l-40)=10 k ( r/4w)，最小需求为:k=q/10(r/4w)0.2 ，l=40+ q (r/4w)0.8/10总成本函数为：tc=10q+kr+lw=10q+q/10((4w)0.2r0.8+(r/4)0.8w0.2)+40w( b)当r=64 ，w=32 时tc=10q+ (2*20.2+0.50.8)32 q/10+1280tc=1280+10q+91.84 q/10=1280+19.184q该技术呈现规模递减。
平狄克微观经济学答案第10-Word文档
第十章 复习题1．该垄断者减少产量，直到边际成本等于边际收益。
2．P MC P E D-=-1该等式表明，当弹性上升（需求变得更加有弹性），弹性相反数的下降和度量市场力的下降，因而当弹性上升（下降），厂商有更少（多）能力使价格高于边际成本。
3．垄断者的产出决定由需求曲线和边际成本决定。
因而需求的变动不仅像竞争的供给曲线那样给出一系列价格和产量，而且需求的变动可以导致价格改变但产量并不变，也可以导致产量改变而价格不变。
他们不存在价格和产量之间的一一对应关系，因自垄断市场没有供给曲线。
4．垄断力量的程度或一个厂商左右市场的力量取决于面对的需求曲线的弹性。
因此如果厂商的需求曲线的弹性小于无穷，厂商就有一些垄断势力。
5．来源于3个方面：（1）市场需求弹性，如，欧佩克利用石油在短期是无弹性而控制油价（2）厂商的数目，如，某3个厂商控制某一产品的市场份额，他们就有了垄断势力（3）厂商间的相互作用，如，几个主要的厂商相互串通，那么他们就能产生垄断势力。
6．同上7．垄断势力的结果是较高的价格和较低的产量，容易使消费者的利益受损,消费者剩余就会减少。
同时厂商可能用一些非生产的方式来保持他的垄断地位，从而使社会成本更大。
8． 藉由在垄断者的取利润最大值的价格下面限制价格，政府能改变厂商的边际收益曲线的形状。
当价格极高被征税的时候，边际收益为比以极高价格量低的量和极高价格相等。
如果政府取输出最大值,它应该将一个价格对手设定为边际成本。
价格在这一个水平下面引诱公司减少制造, 假定边际成本曲线正在以上难以下咽的食物。
调整者的问题要决定垄断的边际成本曲线的形状。
9. 边际的支出是在总支出方面的改变如被购买的量的变化。
对于为购买由于许多厂商竞争的一个厂商，边际的支出和平均支出相等。
所有的厂商应该购买以便最后一个单位的边际价值和在那一个单位上的边际支出相等。
这对两者的竞争买主和垄断者是真实的。
10. 买方垄断势力是购买者影响一种货物价格的能力。
平狄克《微观经济学》第七版·课后习题答案中文word资料68页
第一章复习题1．市场是通过相互作用决定一种或一系列产品价格的买卖双方的集合，因此可以把市场看作决定价格的场所。
行业是出售相同的或紧密相关的产品的厂商的集合，一个市场可以包括许多行业。
2．评价一个理论有两个步骤：首先，需要检验这个理论假设的合理性；第二，把该理论的预测和事实相比较以此来验证它。
如果一个理论无法被检验的话，它将不会被接受。
因此，它对我们理解现实情况没有任何帮助。
3．实证分析解释“是什么”的问题，而规范分析解释的是“应该是什么”的问题。
对供给的限制将改变市场的均衡。
A中包括两种分析，批评这是一种“失败的政策”——是规范分析，批评其破坏了市场的竞争性——是实证分析。
B向我们说明在燃油的配给制下总社会福利的被损坏——是实证分析。
4．由于两个市场在空间上是分离的，商品在两地间的运输是套利实现的条件。
如果运输成本为零，则可以在Oklahoma购买汽油，到New Jersey出售，赚取差价；如果这个差价无法弥补运输成本则不存在套利机会。
5．商品和服务的数量与价格由供求关系决定。
鸡蛋的实际价格从1970年至1985年的下降，一方面是由于人们健康意识的提高而导致鸡蛋需求的减少，同时也因为生产成本的降低。
在这两种因素下，鸡蛋的价格下降了。
大学教育的实际价格的升高，是由于越来越多的人倾向于获得大学教育而导致需求提高，同时教育的成本也在升高。
在这两方面因素作用下，大学教育费用提高了。
6．日圆相对美圆来说，价值升高，升值前相比，兑换同样数量的日圆需要付出更多的美圆。
由汇率的变化引起购买力的变化，在日本市场出售的美国汽车，由于美圆贬值日圆升值，持有日圆的消费者将较以前支付较底的价格；而在美国市场出售的日本汽车，由于日圆升值美圆贬值，持有美圆的消费者将面对较以前提高的价格。
第二章复习题1.假设供给曲线固定，炎热天气通常会引起需求曲线右移，在当前价格上造成短期需求过剩。
消费者为获得冰激凌，愿意为每一单位冰激凌出价更高。
平狄克《微观经济学》课后答案 2
CHAPTER 2THE BASICS OF SUPPLY AND DEMANDThis chapter departs from the standard treatment of supply and demand basics found in most other intermediate microeconomics textbooks by discussing some of the world’s most important markets (wheat, gasoline, and automobiles) and teaching students how to analyze these markets with the tools of supply and demand.Although most of the discussion of economic theory in this chapter serves as a review, the real-world applications of this theory will be enlightening for students, particularly the material covered in Section 2.5 and Examples 2.5 and 2.6.Some problems plague the understanding of supply and demand analysis. One of the most common sources of confusion is between movements along the demand curve and shifts in demand. Through a discussion of the ceteris paribus assumption, stress that when representing a demand function (either with a graph or an equation), all other variables are held constant. Movements along the demand curve occur only with changes in price. As the omitted factors change, the entire demand function shifts. Students may also find a review of how to solve two equations with two unknowns helpful.To stress the quantitative aspects of the demand curve to students, make the distinction between quantity demanded as a function of price, Q = D(P), and the inverse demand function, where price is a function of the quantity demanded, P = D-1(Q). This may clarify the positioning of price on the Y-axis and quantity on the X-axis.Students may also question how the market adjusts to a new equilibrium. One simple mechanism is the partial-adjustment cobweb model. A discussion of the cobweb model (based on traditional corn-hog cycle or any other example) adds a certain realism to the discussion and is much appreciated by students.Although this chapter introduces demand, income, and cross-price elasticities, you may find it more appropriate to return to income and cross-price elasticity after demand elasticity is reintroduced in Chapter 4. If you wait, you should postpone Exercise (7) until income and cross-price elasticities are discussed.1. Suppose that unusually hot weather causes the demand curve for ice cream to shift to the right. Why will the price of ice cream rise to a new market-clearing level?Assume the supply curve is fixed. The unusually hot weather will cause a rightwardshift in the demand curve, creating short-run excess demand at the current price.Consumers will begin to bid against each other for the ice cream, putting upwardpressure on the price. The price of ice cream will rise until the quantity demanded andthe quantity supplied are equal.4. Why do long-run elasticities of demand differ from short-run elasticities? Consider two goods: paper towels and televisions. Which is a durable good? Would you expect the price elasticity of demand for paper towels to be larger in the short-run or in the long-run? Why? What about the price elasticity of demand for televisions?Long-run and short-run elasticities differ based on how rapidly consumers respond toprice changes and how many substitutes are available. If the price of paper towels, anon-durable good, were to increase, consumers might react only minimally in the shortrun. In the long run, however, demand for paper towels would be more elastic as newsubstitutes entered the market (such as sponges or kitchen towels). In contrast, thequantity demanded of durable goods, such as televisions, might change dramatically inthe short run following a price change. For example, the initial influence of a priceincrease for televisions would cause consumers to delay purchases because durablegoods are built to last longer. Eventually consumers must replace their televisions asthey wear out or become obsolete; therefore, we expect the demand for durables to bemore elastic in the long run.5. Explain why, for many goods, the long-run price elasticity of supply is larger than the short-run elasticity.The elasticity of supply is the percentage change in the quantity supplied divided by thepercentage change in price. An increase in price induces an increase in the quantitysupplied by firms. Some firms in some markets may respond quickly and cheaply toprice changes. However, other firms may be constrained by their production capacity inthe short run. The firms with short-run capacity constraints will have a short-runsupply elasticity that is less elastic. However, in the long run all firms can increasetheir scale of production and thus have a larger long-run price elasticity.6. Suppose the government regulates the prices of beef and chicken and sets them below their market-clearing levels. Explain why shortages of these goods will develop and what factors will determine the sizes of the shortages. What will happen to the price of pork? Explain briefly.If the price of a commodity is set below its market-clearing level, the quantity that firmsare willing to supply is less than the quantity that consumers wish to purchase. Theextent of the excess demand implied by this response will depend on the relativeelasticities of demand and supply. For instance, if both supply and demand are elastic,the shortage is larger than if both are inelastic. Factors such as the willingness ofconsumers to eat less meat and the ability of farmers to change the size of their herdsand produce less determine these elasticities and influence the size of excess demand.Rationing will result in situations of excess demand when some consumers are unableto purchase the quantities desired. Customers whose demands are not met willattempt to purchase substitutes, thus increasing the demand for substitutes and raisingtheir prices. If the prices of beef and chicken are set below market-clearing levels, theprice of pork will rise.7. In a discussion of tuition rates, a university official argues that the demand for admission is completely price inelastic. As evidence she notes that while the university has doubled its tuition (in real terms) over the past 15 years, neither the number nor quality of students applying has decreased. Would you accept this argument? Explain briefly. (Hint: The official makes an assertion about the demand for admission, but does she actually observe a demand curve? What else could be going on?)If demand is fixed, the individual firm (a university) may determine the shape of thedemand curve it faces by raising the price and observing the change in quantity sold.The university official is not observing the entire demand curve, but rather only theequilibrium price and quantity over the last 15 years. If demand is shifting upward, assupply shifts upward, demand could have any elasticity. (See Figure 2.7, for example.)Demand could be shifting upward because the value of a college education hasincreased and students are willing to pay a high price for each opening. More marketc. A drought shrinks the apple crop to one-third its normal size.The supply curve would shift in, causing the equilibrium price to rise and theequilibrium quantity to fall.d. Thousands of college students abandon the academic life to become apple pickers.The increased supply of apple pickers will lead to a decrease in the cost of bringingapples to market. The decreased cost of bringing apples to market results in anoutward shift of the supply curve of apples and causes the equilibrium price to fall andthe equilibrium quantity to increase.e. Thousands of college students abandon the academic life to become apple growers.This would result in an outward shift of the supply curve for apples, causing theequilibrium price to fall and the equilibrium quantity to increase.1. Consider a competitive market for which the quantities demanded and supplied (per year) at various prices are given as follows:Price($)Demand (millions) Supply (millions) 6022 14 8020 16 10018 18 12016 20 a. Calculate the price elasticity of demand when the price is $80. When the price is$100.We know that the price elasticity of demand may be calculated using equation 2.1 fromthe text:E Q Q P PP Q Q PD D D D D ==∆∆∆∆. With each price increase of $20, the quantity demanded decreases by 2. Therefore,∆∆Q P DF HG I K J =-=-22001.. At P = 80, quantity demanded equals 20 andE D =F HG I KJ -=-802001040...b g Similarly, at P = 100, quantity demanded equals 18 andE D =F HG I K J -=-1001801056...b g b. Calculate the price elasticity of supply when the price is $80. When the price is $100.The elasticity of supply is given by:E Q Q P P Q Q PS S S S S ==∆∆∆∆. With each price increase of $20, quantity supplied increases by 2. Therefore,∆∆Q SF HG I K J ==22001.. At P = 80, quantity supplied equals 16 andE S =F HG I KJ =80160105..bg .Similarly, at P = 100, quantity supplied equals 18 andE S=FH GIK J= 1001801056...bgc. What are the equilibrium price and quantity?The equilibrium price and quantity are found where the quantity supplied equals thequantity demanded at the same price. As we see from the table, the equilibrium priceis $100 and the equilibrium quantity is 18 million.d. Suppose the government sets a price ceiling of $80. Will there be a shortage, and, ifso, how large will it be?With a price ceiling of $80, consumers would like to buy 20 million, but producers willsupply only 16 million. This will result in a shortage of 4 million.2. Refer to Example 2.3 on the market for wheat. Suppose that in 1985 the Soviet Union hadbought an additional 200 million bushels of U.S. wheat. What would the free market price of wheat have been and what quantity would have been produced and sold by U.S. farmers?The following equations describe the market for wheat in 1985:QS= 1,800 + 240PandQD= 2,580 - 194P.If the Soviet Union had purchased an additional 200 million bushels of wheat, the newdemand curve 'Q D, would be equal to Q ED + 200, or'Q D= (2,580 - 194P) + 200 = 2,780 - 194PEquating supply and the new demand, we may determine the new equilibrium price,1,800 + 240P = 2,780 - 194P, or434P = 980, or P* = $2.26 per bushel.To find the equilibrium quantity, substitute the price into either the supply or demandequation, e.g.,QS= 1,800 + (240)(2.26) = 2,342andQD= 2,780 - (194)(2.26) = 2,342.3. The rent control agency of New York City has found that aggregate demand is QD= 100 - 5P measured in tens of thousands of apartments, and price, the average monthly rental rate, P, with quantity measured in hundreds of dollars. The agency also noted that the increase in Q at lower P results from more three-person families coming into the city from Long Island and demanding apartments. The city’s board of realtors acknowledges that this is agood demand estimate and has shown that supply is QS= 50 + 5P.a. If both the agency and the board are right about demand and supply, what is the freemarket price? What is the change in city population if the agency sets a maximum average monthly rental of $100, and all those who cannot find an apartment leave the city?To find the free market price for apartments, set supply equal to demand:100 - 5P = 50 + 5P, or P = $500.Substituting the equilibrium price into either the demand or supply equation todetermine the equilibrium quantity:QD= 100 - (5)(5) = 75andQ S = 50 + (5)(5) = 75.We find that at the rental rate of $500, 750,000 apartments are rented.If the rent control agency sets the rental rate at $100, the quantity supplied would thenbe 550,000 (Q S = 50 + (5)(100) = 550), a decrease of 200,000 apartments from the freemarket equilibrium. (Assuming three people per family per apartment, this wouldimply a loss of 600,000 people.) At the $100 rental rate, the demand for apartments is950,000 units, and the resultant shortage is 400,000 units.b. Suppose the agency bows to the wishes of the board and sets a rental of $900 permonth on all apartments to allow landlords a “fair” rate of return. If 50 percent of any long-run increases in apartment offerings comes from new construction, how many apartments are constructed?At a rental rate of $900, the supply of apartments would be 50 + 5(9) = 95, or 950,000units, which is an increase of 200,000 units over the free market equilibrium.Therefore, (0.5)(200,000) = 100,000 units would be constructed. Note, however, thatsince demand is only 550,000 units, 400,000 units would go unrented.4. Much of the demand for U.S. agricultural output has come from other countries. From Example 2.3, total demand is Q = 3,550 - 266P . In addition, we are told that domestic demand is Q d = 1,000 - 46P . Domestic supply is Q S = 1,800 + 240P . Suppose the export demand for wheat falls by 40 percent.a. U.S. farmers are concerned about this drop in export demand. What happens to thefree market price of wheat in the United States? Do the farmers have much reason to worry?Given total demand, Q = 3,550 - 266P , and domestic demand, Q d = 1,000 - 46P , we maysubtract and determine export demand, Q e = 2,550 - 220P .The initial market equilibrium price is found by setting total demand equal to supply:3,550 - 266P - 1,800 + 240P , orP = $3.46.There are two different ways to handle the 40 percent drop in demand. One way is toassume that the demand curve shifts down so that at all prices demand decreases by 40percent. The second way is to rotate the demand curve in a clockwise manner aroundthe vertical intercept (i.e. in the current case the demand curve would becomeQ = 3,550 - 159.6P ). We apply the former approach in the solution to exercises here.Regardless of the two approaches, the effect on prices and quantity will be qualitativelythe same, but will differ quantitatively.Therefore, if export demand decreases by 40 percent, total demand becomesQ D = Q d + 0.6Q e = 1,000 - 46P + (0.6)(2,550 - 220P ) = 2,530 - 178P .Equating total supply and total demand,1,800 + 240P = 2,530 - 178P , orP = $1.75,which is a significant drop from the market-clearing price of $3.46 per bushel. At thisprice, the market-clearing quantity is 2,219 million bushels. Total revenue hasdecreased from $9.1 billion to $3.9 billion. Most farmers would worry.b. Now suppose the U.S. government wants to buy enough wheat each year to raise theprice to $3.00 per bushel. Without export demand, how much wheat would the government have to buy each year? How much would this cost the government?With a price of $3, the market is not in equilibrium. Demand = 1000 - 46(3) = 862.Supply = 1800 + 240(3) = 2,520, and excess supply is therefore 2,520 - 862 = 1,658. Thegovernment must purchase this amount to support a price of $3, and will spend $3(1.66million) = $5.0 billion per year.5. In Example 2.6 we examined the effect of a 20 percent decline in copper demand on the price of copper, using the linear supply and demand curves developed in Section 2.5. Suppose the long-run price elasticity of copper demand were -0.4 instead of -0.8.a. Assuming, as before, that the equilibrium price and quantity are P* = 75 cents perpound and Q* = 7.5 million metric tons per year, derive the linear demand curve consistent with the smaller elasticity.Following the method outlined in Section 2.5, we solve for a and b in the demandequation Q D = a - bP . First, we know that for a linear demand function E b P D =-F H G I KJ *. Here E D = -0.4 (the long-run price elasticity), P* = 0.75 (the equilibrium price), and Q* =7.5 (the equilibrium quantity). Solving for b , -=-F H I K0407575...b , or b = 4. To find the intercept, we substitute for b , Q D (= Q *), and P (= P *) in the demandequation:7.5 = a - (4)(0.75), or a = 10.5.The linear demand equation consistent with a long-run price elasticity of -0.4 isthereforeQ D = 10.5 - 4P .b. Using this demand curve, recalculate the effect of a 20 percent decline in copperdemand on the price of copper.The new demand is 20 percent below the original (using our convention that the wholedemand curve is shifted down by 20 percent):'Q D =-=-0810548432....a f a fP P . Equating this to supply,8.4 - 3.2P = -4.5 + 16P , orP = 0.672.With the 20 percent decline in the demand, the price of copper falls to 67.2 cents perpound.6. Example 2.7 analyzes the world oil market. Using the data given in that example,a. Show that the short-run demand and competitive supply curves are indeed given byD = 24.08 - 0.06PS C = 11.74 + 0.07P .First, considering non-OPEC supply:S c = Q * = 13.With E S = 0.10 and P * = $18, E S = d (P */Q *) implies d = 0.07.Substituting for d , S c , and P in the supply equation, c = 11.74 and S c = 11.74 + 0.07P .Similarly, since Q D = 23, E D = -b (P */Q *) = -0.05, and b = 0.06. Substituting for b , Q D = 23, and P = 18 in the demand equation gives 23 = a - 0.06(18), so that a = 24.08.Hence Q D = 24.08 - 0.06P .b. Show that the long-run demand and competitive supply curves are indeed given byD = 32.18 - 0.51PS C = 7.78 + 0.29P .As above, E S = 0.4 and E D = -0.4: E S = d (P */Q *) and E D = -b(P*/Q*), implying 0.4 = d (18/13)and -0.4 = -b (18/23). So d = 0.29 and b = 0.51.Next solve for c and a :S c = c + dP and Q D = a - bP , implying 13 = c + (0.29)(18) and 23 = a - (0.51)(18).So c = 7.78 and a = 32.18.c. Use this model to calculate what would happen to the price of oil in the short-runand the long-run if OPEC were to cut its production by 6 billion barrels per year.With OPEC’s supply reduced from 10 bb/yr to 4 bb/yr, add this lower supply of 4 bb/yr to the short-run and long-run supply equations:S c ' = 4 + S c = 11.74 + 4 + 0.07P = 15.74 + 0.07P and S " = 4 + S c = 11.78 + 0.29P .These are equated with short-run and long-run demand, so that:15.74 + 0.07P = 24.08 - 0.06P ,implying that P = $64.15 in the short run; and11.78 + 0.29P = 32.18 - 0.51P ,implying that P = $24.29 in the long run.7.Refer to Example 2.8, which analyzes the effects of price controls on natural gas. a. Using the data in the example, show that the following supply and demand curvesdid indeed describe the market in 1975:Supply: Q = 14 + 2P G + 0.25P ODemand: Q = -5P G + 3.75P Owhere P G and P O are the prices of natural gas and oil, respectively. Also, verify that if the price of oil is $8.00, these curves imply a free market price of $2.00 for natural gas.To solve this problem, we apply the analysis of Section 2.5 to the definition of cross-price elasticity of demand given in Section 2.3. For example, the cross-price-elasticity of demand for natural gas with respect to the price of oil is:E Q P P Q GO G O G G=F HG I K J FH GI KJ ∆∆. ∆∆Q P G O F H G IK J is the change in the quantity of natural gas demanded, because of a small change in the price of oil. For linear demand equations,∆∆Q P G O F H G I K J is constant. If we represent demand as:Q G = a - bP G + eP O(notice that income is held constant), then∆∆Q P G OF HG I K J = e . Substituting this into the cross-price elasticity, E e P Q PO O G=F H G I K J **, where P O * and Q G * are the equilibrium price and quantity. We know that P O * = $8 and Q G* = 20 trillion cubic feet (Tcf). Solving for e , 15820.=F H G I KJ e , or e = 3.75. Similarly, if the general form of the supply equation is represented as:Q G = c + dP G + gP O , the cross-price elasticity of supply is g P Q OG**F H G I K J , which we know to be 0.1. Solving for g , ⎪⎭⎫ ⎝⎛=2081.0g , or g = 0.25. The values for d and b may be found with equations 2.5a and 2.5b in Section 2.5. Weknow that E S = 0.2, P* = 2, and Q* = 20. Therefore,⎪⎭⎫ ⎝⎛=2022.0d , or d = 2.Also, E D = -0.5, so⎪⎭⎫ ⎝⎛=-2025.0b , or b = -5. By substituting these values for d, g, b , and e into our linear supply and demandequations, we may solve for c and a :20 = c + (2)(2) + (0.25)(8), or c = 14,and20 = a - (5)(2) + (3.75)(8), or a = 0.If the price of oil is $8.00, these curves imply a free market price of $2.00 for naturalgas. Substitute the price of oil in the supply and demand curves to verify theseequations. Then set the curves equal to each other and solve for the price of gas.14 + 2P G + (0.25)(8) = -5P G + (3.75)(8), 7P G = 14, orP G = $2.00.b. Suppose the regulated price of gas in 1975 had been $1.50 per million cubic feet,instead of $1.00. How much excess demand would there have been?With a regulated price of $1.50 for natural gas and a price of oil equal to $8.00 perbarrel,Demand: Q D = (-5)(1.50) + (3.75)(8) = 22.5, andSupply: Q S = 14 + (2)(1.5) + (0.25)(8) = 19.With a supply of 19 Tcf and a demand of 22.5 Tcf, there would be an excess demand of3.5 Tcf.c. Suppose that the market for natural gas had not been regulated. If the price of oilhad increased from $8 to $16, what would have happened to the free market price of natural gas?If the price of natural gas had not been regulated and the price of oil had increasedfrom $8 to $16, thenDemand: Q D = -5P G + (3.75)(16) = 60 - 5P G , andSupply: Q S = 14 + 2P G + (0.25)(16) = 18 + 2P G .Equating supply and demand and solving for the equilibrium price,18 + 2P G = 60 - 5P G , or P G = $6.The price of natural gas would have tripled from $2 to $6.。
平狄克微观经济学答案第1-3章11页word
第一章复习题1．市场是通过相互作用决定一种或一系列产品价格的买卖双方的集合，因此可以把市场看作决定价格的场所。
行业是出售相同的或紧密相关的产品的厂商的集合，一个市场可以包括许多行业。
2．评价一个理论有两个步骤：首先，需要检验这个理论假设的合理性；第二，把该理论的预测和事实相比较以此来验证它。
如果一个理论无法被检验的话，它将不会被接受。
因此，它对我们理解现实情况没有任何帮助。
3．实证分析解释“是什么”的问题，而规范分析解释的是“应该是什么”的问题。
对供给的限制将改变市场的均衡。
A中包括两种分析，批评这是一种“失败的政策”——是规范分析，批评其破坏了市场的竞争性——是实证分析。
B向我们说明在燃油的配给制下总社会福利的被损坏——是实证分析。
4．由于两个市场在空间上是分离的，商品在两地间的运输是套利实现的条件。
如果运输成本为零，则可以在Oklahoma购买汽油，到New Jersey出售，赚取差价；如果这个差价无法弥补运输成本则不存在套利机会。
5．商品和服务的数量与价格由供求关系决定。
鸡蛋的实际价格从1970年至1985年的下降，一方面是由于人们健康意识的提高而导致鸡蛋需求的减少，同时也因为生产成本的降低。
在这两种因素下，鸡蛋的价格下降了。
大学教育的实际价格的升高，是由于越来越多的人倾向于获得大学教育而导致需求提高，同时教育的成本也在升高。
在这两方面因素作用下，大学教育费用提高了。
6．日圆相对美圆来说，价值升高，升值前相比，兑换同样数量的日圆需要付出更多的美圆。
由汇率的变化引起购买力的变化，在日本市场出售的美国汽车，由于美圆贬值日圆升值，持有日圆的消费者将较以前支付较底的价格；而在美国市场出售的日本汽车，由于日圆升值美圆贬值，持有美圆的消费者将面对较以前提高的价格。
第二章复习题1.假设供给曲线固定，炎热天气通常会引起需求曲线右移，在当前价格上造成短期需求过剩。
消费者为获得冰激凌，愿意为每一单位冰激凌出价更高。
微观经济学(平狄克鲁宾费尔德)第六版课后答案--微观经济学 英文原版-CH02PINDYCK
The Basics of Supply and Demand
Introduction
What are supply and demand? What is the market mechanism? What are the effects of changes in market equilibrium? What are elasticities of supply and demand?
Produced Q1 at P1 and Q0 at P2 Now produce Q2 at P1 and Q1 at P2 Supply curve shifts right to S’
P
S S’
P1 P2
Q0
©2005 Pearson Education, Inc. Chapter 2
QD QD(P)
©2005 Pearson Education, Inc. Chapter 2 10
The Demand Curve
Price ($ per unit) The demand curve slopes downward, demonstrating that consumers are willing to buy more at a lower price as the product becomes relatively cheaper.
Q1
©2005 Pearson Education, Inc.
Q2
Chapter 2
Quantity
6
The Supply Curve
Other Variables Affecting Supply
Costs of Production
平狄克微观经济学答案——第10章卖方垄断与买方垄断
P MC 1
P
Ed
或者
P MC
1
1 Ed
在题目中， Ed 2.0 ，所以1/ Ed 1/ 2 ，价格可以定为：
P MC 2MC 1 2
因此，当 MC 升高 25％，价格也应当升高 25％。当 MC＝$20,.P=$40。当 MC 升高到 $20*(1.25)＝$25 时，价格应当升到$50，升高 25％。 4．一厂商面临如下的平均收益（需求）曲线：
2所以2me曲线于边际价值曲线交于2?depmcp1?????d?????????????dmcp11?在题目中?e211??de价格可以定为
第三部分 企业结构 第十章 市场势力：卖方垄断与买方垄断
教学注解 这一章同时涵盖了卖方垄断与买方垄断两部分，旨在揭示两种类型市场势 力的相似性。本章开始的 1－4 节讨论的是卖方垄断。第 5 节首先讨论买方垄断， 然后提出卖方垄断与买方垄断的指导性比较。第 6 节讨论买方势力的来源及其 社会成本。第 7 节以对反垄断法的讨论终结本章。如果时间较紧，你可以只讲 述有关卖方垄断的前 4 节而略去本章其余部分。你可以讲述第 7 节即便略去了 5、6 节。第 1 节最后有关复合企业的部分同样可以略去。 尽管第 8 章讲述了利润最大化的一般规则，你应当通过对方程 10.1 的推导 复习边际收入及供给的价格弹性。对方程 10.1 推导的讨论有助于说明图形 10.3 的几何意义。指出对于买方垄断者而言，由于利润最大化处的价格及产量所对 应的边际收入为正，该产量处的弹性较大。同时，方程 10.1 直接引出了 10.2 节 的勒纳指数。这为卖方垄断市场势力的讨论奠定了坚实的基础。比如说，如果 Ed 较大（如由于高度替代品），那么，（1）需求曲线相对平坦，（2）边际收入 曲线相对平坦（尽管比需求曲线陡峭），（3）卖方垄断者难以使价格超出边际成 本很多。为了强调这一点，可以引入非线性需求曲线，比如，展示单位弹性需 求曲线的边际收入曲线的位置。一旦这些概念讲清楚了，对于面对非线性需求 曲线的卖方垄断厂商征税效果的讨论就不是那么困难了。 市场势力的社会成本是课堂讨论的较好话题。对于卖方垄断造成的无谓损 失可以与第 9 章的市场干预分析加以比较引出。比如将图 10.10 与图 9.5 进行比 较。考虑到练习（9），（13），（15）涉及了“拐折的边际收入曲线”，如果你要 布置这些作业，你应当讲解图 10.11。尽管图 10.11 很复杂，在这里涉及有助于 12 章重现时的理解。
平狄克《微观经济学》(第7、8版)章节习题精编详解(供给和需求的基本原理)
第2章供给和需求的基本原理一、单项选择题1．若需求曲线为直角双曲线，则商品价格的上升将引起消费者在该商品上的总花费（）。
A．增加B．下降C．不变D．以上均有可能【答案】C【解析】因为直角双曲线上点弹性处处相等且等于1，即处处为单位弹性。
单位弹性的商品降价或提高价格对厂商的销售收入都没有影响，因此消费者在该商品上的总花费不变。
2．下列说法中正确的是（）。
A．收入弹性取决于商品本身的属性B．不同商品在一定收入范围内具有相同的收入弹性C．同一商品在不同的收入范围内具有相同的收入弹性D．同一商品在不同的收入范围内具有不同的收入弹性【答案】D【解析】收入弹性取决于商品本身的属性和消费者的收入水平。
例如，对同一个消费者而言，任一收入水平下，都会有必需品和奢侈品，其收入弹性自然不同；同时，对同一个消费者而言，收入水平极低时，水果是奢侈品，收入弹性，但收入水平提高后，也许就成了必需品了，收入弹性。
因此，商品不同、收入水平不同，都会有不同的收入弹性。
3．需求价格弹性等于（ ）。
A ．需求曲线上两点间价格的变动量除以需求的变动量B ．需求曲线上需求的变动量除以价格的变动量C ．需求曲线上价格的变动比除以需求的变动比D ．需求曲线上需求的变动比除以价格的变动比【答案】D【解析】需求价格弹性表示商品需求量对自身价格变动的反应程度，即：。
4．商品是正常品，则当其价格下降时（ ）。
A ．商品的需求量会下降B ．商品的需求会下降C ．商品的需求量会上升D ．商品的需求会上升【答案】C【解析】需求变动是指价格之外的变量变化对消费者决策的影响，它与整个需求曲线的移动是对应的；需求量的变动则是价格变化对消费者均衡购买量的影响，它对应于一条需求曲线上点的移动。
因此当商品价格下降时，其需求量会上升。
1I E >1I E <//P Q Q E P P∆=∆x x x x x x5．如果某商品的价格下降5%后，消费者对此商品的货币支出增加了2%，则需求曲线在这一区域内的需求弹性为（ ）。
平狄克微观经济学课后习题答案(中文)第九版
平狄克微观经济学课后习题答案(中文)第九版第一章经济学的研究对象和方法习题1-1答案：经济学的研究对象是人类的经济活动，包括生产、交换、分配和消费等方面。
经济学的研究方法主要包括观察、实证分析和理论分析等。
习题1-2答案：观察是经济学研究的基础，通过观察可以获得经济现象的真实情况。
实证分析是基于观察数据进行的定量分析，通过统计分析等方法来验证经济理论的有效性。
理论分析是通过构建模型和假设来研究和解释经济现象的原因和机制。
习题1-3答案：经济学的分类有宏观经济学和微观经济学两个主要方向。
宏观经济学研究整个经济体系的总体运行规律，涉及国民经济的总量问题；微观经济学研究个体经济单位（如个人、家庭、企业）的经济行为和决策，涉及资源配置和效率问题。
习题1-4答案：正式的经济学的定义是一个关于个体与群体选择的社会科学。
它研究人们如何利用有限的资源，以满足无限的欲望。
经济学通过分析经济行为的原理和规律，帮助人们做出更好的经济决策，实现资源的高效配置和社会福利的最大化。
第二章需求、供给与市场均衡习题2-1答案：需求是指个人或市场上愿意购买某种商品或服务的能力和意愿。
供给是指个人或企业愿意出售某种商品或服务的能力和意愿。
习题2-2答案：需求曲线是描述消费者对某种商品或服务需求量与价格之间关系的曲线。
供给曲线是描述生产者或企业对某种商品或服务供给量与价格之间关系的曲线。
习题2-3答案：当市场需求量大于市场供给量时，市场处于短缺状态，价格将上涨；当市场供给量大于市场需求量时，市场处于过剩状态，价格将下降。
只有当市场需求量等于市场供给量时，市场达到均衡状态，价格稳定。
习题2-4答案：市场需求量变化的因素包括消费者收入、商品价格、相关商品价格和个人偏好等。
市场供给量变化的因素包括生产成本、生产技术、生产要素价格和政府政策等。
第三章边际分析及其应用习题3-1答案：边际分析是指在某一决策过程中，考察增加或减少一单元该决策的收益或成本的变化量。
(NEW)平狄克《微观经济学》(第7、8版)章节习题精编详解
目 录第1篇 导论：市场和价格第1章 绪 论第2章 供给和需求的基本原理第2篇 生产者、消费者与竞争性市场第3章 消费者行为第4章 个人需求和市场需求第5章 不确定性与消费者行为第6章 生 产第7章 生产成本第8章 利润最大化与竞争性供给第9章 竞争性市场分析第3篇 市场结构与竞争策略第10章 市场势力：垄断和买方垄断第11章 有市场势力的定价第12章 垄断竞争和寡头垄断第13章 博弈论与竞争策略第14章 投入要素市场第15章 投资、时间与资本市场第4篇 信息、市场失灵与政府的角色第16章 一般均衡与经济效率第17章 信息不对称的市场第18章 外部性和公共物品附 录 指定平狄克《微观经济学》教材为考研参考书目的院校列表第1篇 导论：市场和价格第1章 绪 论一、单项选择题1．经济学可以被定义为（ ）。
A ．政府对市场制度的干预B ．企业赚取利润的活动C ．研究稀缺资源如何有效配置的问题D ．个人的生财之道2．经济物品是指（ ）。
A ．有用的东西B ．稀缺的物品C ．要用钱购买的物品D ．有用且稀缺的物品C【答案】经济学是研究人们和社会如何做出选择，来使用可以有其他用途的稀缺的经济资源在现在或是将来生产各种物品，并把物品分配给社会的各个成员或集团以供消费之用的一门社会科学。
【解析】D【答案】现实世界中绝大多数的物品都是不能自由取得的，因为资【解析】3．一个经济体必须作出的基本选择是（ ）。
A ．生产什么B ．生产多少，何时生产C ．为谁生产D ．以上都是4．宏观经济学与微观经济学的关系是（ ）。
A ．相互独立的B ．两者建立在共同的理论基础上C ．两者既有联系又有矛盾D ．毫无联系源是稀缺的，要获得这些有限的物品就必须付出代价，这种物品就被称为“经济物品”。
D【答案】经济学所要解决的问题包括：①生产什么；②如何生产；③为谁生产；④何时生产。
【解析】C【答案】宏观经济学所研究的总量经济特征正是由经济体系中无数微观主体（家庭和厂商）的经济行为所决定的，因而微观经济主体的决策行为就构成了宏观经济分析的基础，宏观经济学需要构建自己的微观基础。
平狄克微观经济学答案——第8章 利润最大化和竞争性供给
第八章利润最大化和竞争性供给教学笔记这一章确定了追求利润最大化的厂商的行为动机，揭示了这些厂商在竞争性市场的相互影响和作用。
这一章的每一节都很重要，它们构建了对竞争性市场供给一方的彻底完全的认识。
在学习这本教科书的第三部分之前，建立这样一个基础是非常必要的。
虽然这一章的材料都写得很清楚易懂，但是学生可能还是会对有些概念、思想感到很难理解，比如说那些有关厂商应该怎样选择最佳生产数量的思想、有关厂商怎样应用我们前面学习过的成本曲线的思想，等等。
这里有一个讲课的建议：花些时间研究与这一章的最后部分的习题中用到的表格相类似的表格。
研究一些与此类表格有关的例题对于学生理解不同类型的成本，以及相应的厂商的最佳产量是有帮助的。
8.1节确定了完全竞争市场的三个基本假设，8.2节对“厂商以利润最大化为经营目标”这一假设进行了讨论。
8.3节和8.5节对厂商的供给曲线进行了推导，8.1节和8.2节为8.3节、8.5节中供给曲线的推导打下了基础。
8.3节推导出一个一般性的结论：只要边际收入等于边际成本，厂商就应当生产。
这一节接下来确定了完全竞争（一个特殊的案例）的条件之一：价格等于边际收入，这个结论是8.1节中“接受价格”这个假设的直接的逻辑结果。
如果你的学生掌握微积分，那么通过对利润函数关于产量q求微分，可以导出边际成本与边际收入相等。
如果你的学生还没有掌握微积分，那么可以通过对数据表格的多加研究来理解当边际收入和边际成本相等时厂商能达到利润最大化目标这个结论。
这里有一点需要强调：完全竞争市场上，每个厂商只能通过产量的变化而不能通过价格的变化来取得最大利润。
为了正确理解完全竞争市场，我们在提出有关完全竞争市场的假设之前，也要对卖方垄断、寡头卖方垄断和垄断性竞争有一定的了解。
将讨论限定一个专门的范围，这个范围包括确定一个行业里有多少厂商、这个行业是否有进入壁垒、各个厂商的产品是否存在差异，以及行业里每个厂商对其他厂商对于其价格、数量方面的决策的反应做出的假设。
平狄克《微观经济学》课后答案 7-8
CHAPTER 7THE COST OF PRODUCTIONIn this chapter, it is easy for the students to concentrate too much on definitions and geometry and lose focus on the economics. Therefore, keep in mind the key concepts: opportunity cost, short-run average and marginal cost, cost minimization, and long-run average cost. These concepts can be illuminated with the supplementary material provided at the end of the chapter, which includes sections on economies of scope, learning curves, and estimating and predicting costs. The Appendix presents the calculus of constrained optimization, as applied to cost minimization. All exercises involve some algebra or geometry: Exercises (12) and (13) are time consuming, but rewarding.Opportunity cost is the conceptual base of this chapter. While most students think of costs in accounting terms, they must develop an understanding of the distinction between accounting, economic, and opportunity costs. One source of confusion is the opportunity cost of capital, i.e., why the rental rate on capital must be considered explicitly by economists. It is important, for example, to distinguish between the purchase price of capital equipment and the opportunity cost of using the equipment. The opportunity cost of a person’s tim e also leads to some confusion for students.Following the discussion of opportunity cost, the chapter diverges in two directions: one path introduces types of cost and cost curves, and the other focuses on cost minimization. Both directions converge with the discussion of long-run average cost.The geometry of total, fixed, variable, average, and marginal costs can prove to be tedious. An emphasis on the following issues helps students master this topic: 1) the relationship between the production function, diminishing returns in the short run, input prices, and the shapes of the various cost curves; 2) the distinction between total, average, and marginal; and 3) the reasonableness of the assumption of constant input prices (note that this assumption w ill be relaxed in Chapter 10’s discussion of monopsony). The determination of the cost-minimizing quantity is crucial to understanding Chapters 8 and 10. The concept of duality (minimizing cost subject to a given level of production) is equivalent to maximizing output subject to a given level of total cost) clarifies this concept for students.A clear understanding of short-run cost and cost minimization is necessary for the derivation of long-run average cost. With long-run costs, stress that firms are operating on short-run cost curves at each level of the fixed factor and that long-run costs do not exist separately from short-run costs. Exercise (6) illustrates the relationship between long-run cost and cost minimization, with an emphasis on the importance of the expansion path. Stress the connection between the shape of a long-run cost curve and returns to scale. While Section 7.7 is starred, it does not require calculus. Example 7.5 “Cost Functions for Electric Power,” gives students another vie w of long-run average cost and allows for discussion of minimum efficient scale, an important determinant of industry structure.1. A firms pays its accountant an annual retainer of $10,000. Is this an explicit or implicit cost?Explicit costs are actual outlays. They include all costs that involve a monetary transaction.An implicit cost is an economic cost that does not necessarily involve a monetary transaction, butstill involves the use of resources. When a firm pays an annual retainer of $10,000, there is amonetary transaction. The accountant trades his or her time in return for money. Therefore,an annual retainer is an explicit cost.2. The owner of a small retail store does her own accounting work. How would you measure the opportunity cost of her work?Opportunity costs are measured by comparing the use of a resource with its alternative uses.The opportunity cost of doing accounting work is the time not spent in other ways, i.e., time suchas running a small business or participating in leisure activity. The economic cost of doingaccounting work is measured by computing the monetary amount that the time would be worth inits next best use.3. Suppose a chair manufacturer finds that the marginal rate of technical substitution of capital for labor in his production process is substantially greater than the ratio of the rental rate on machinery to the wage rate for assembly-line labor. How should he alter his use of capital and labor to minimize the cost of production?To minimize cost, the manufacturer should use a combination of capital and labor so the rate atwhich he can trade capital for labor in his production process is the same as the rate at which hecan trade capital for labor in external markets. The manufacturer would be better off if heincreased his use of capital and decreased his use of labor, decreasing the marginal rate oftechnical substitution, MRTS. He should continue this substitution until his MRTS equals theratio of the rental rate to the wage rate.4. Why are isocost lines straight lines?The isocost line represents all possible combinations of labor and capital that may be purchasedfor a given total cost. The slope of the isocost line is the ratio of the input prices of labor andcapital. If input prices are fixed, then the ratio of these prices is clearly fixed and the isocost lineis straight. Only when the ratio or factor prices change as the quantities of inputs change is theisocost line not straight.5. If the marginal cost of production is increasing, does this tell you whether the average variable cost is increasing or decreasing? Explain.Marginal cost can be increasing while average variable cost is either increasing or decreasing. Ifmarginal cost is less (greater) than average variable cost, then each additional unit is adding less(more) to total cost than previous units added to the total cost, which implies that the AVCdeclines (increases). Therefore, we need to know whether marginal cost is greater than averagecost to determine whether the AVC is increasing or decreasing.6. If the marginal cost of production is greater than the average variable cost, does this tell you whether the average variable cost is increasing or decreasing? Explain.If the average variable cost is increasing (decreasing), then the last unit produced is adding more(less) to total variable cost than the previous units did, on average. Therefore, marginal cost isabove (below) average variable cost. If marginal cost is above average variable cost, averagevariable cost is also increasing.7. If the firm’s average cost curves are U-shaped, why does its average variable cost curve achieve its minimum at a lower level of output than the average total cost curve?Total cost is equal to fixed plus variable cost. Average total cost is equal to average fixed plusaverage variable cost. When graphed, the difference between the U-shaped total cost andaverage variable cost curves is the average fixed cost curve. If fixed cost is greater than zero, theminimum of average variable cost must be less than the minimum average total cost.8. If a firm enjoys increasing returns to scale up to a certain output level, and then constant returns to scale, what can you say about the shape of the firm’s long-run average cost curve?When the firm experiences increasing returns to scale, its long-run average cost curve isdownward sloping. When the firm experiences constant returns to scale, its long-run averagecost curve is horizontal. If the firm experiences increasing returns to scale, then constantreturns to scale, its long-run average cost curve falls, then becomes horizontal.9. How does a change in the price of one input change the firm’s long-run expansion path?The expansion path describes the combination of inputs for which the firm chooses to minimizecost for every output level. This combination depends on the ratio of input prices: if the price ofone input changes, the price ratio also changes. For example, if the price of an input increases,less of the input may be purchased for the same total cost. The intercept of the isocost line onthat input’s axis moves closer to the origin. Also, the slope of the isocost line, the price ratio,changes. As the price ratio changes, the firm substitutes away from the now more expensiveinput toward the cheaper input. Thus, the expansion path bends toward the axis of the nowcheaper input. See Exercise (7.6).10. Distinguish between economies of scale and economies of scope. Why can one be present without the other?Economies of scale refer to the production of one good and occur when proportionate increases inall inputs lead to a more-than-proportionate increase in output. Economies of scope refer to theproduction of more than one good and occur when joint output is less costly than the sum of thecosts of producing each good or service separately. There is no direct relationship betweenincreasing returns to scale and economies of scope, so production can exhibit one without theother. See Exercise (13) for a case with constant product-specific returns to scale andmultiproduct economies of scope.1. Assume a computer firm’s marginal costs of production are constant at $1,000 per computer. However, the fixed costs of production are equal to $10,000.a. Calculate the firm’s average variable cost and average total cost curves.The variable cost of producing an additional unit, marginal cost, is constant at $1,000, so theaverage variable cost is constant at $1,000, ()000,1$000,1$=QQ . Average fixed cost is $10,000Q. Average total cost is the sum of average variable cost and average fixed cost: ATC Q=+$1,$10,.000000 b. If the firm wanted to minimize the average total cost of production, would it choose to be verylarge or very small? Explain.The firm should choose a very large output because average total cost decreases with increase inQ . As Q becomes infinitely large, ATC will equal $1,000.2. If a firm hires a currently unemployed worker, the opportunity cost of utilizing t he worker’s service is zero. Is this true? Discuss.From the worker’s perspective, the opportunity cost of his or her time is the time not spent inother ways, including time spent in personal or leisure activities. Certainly, the opportunity costof hiring an unemployed mother of pre-school children is not zero! While it might be difficult toassign a monetary value to the time of an unemployed worker, we can not conclude that it is zero.From the perspective of the firm, the opportunity cost of hiring the worker is not zero, and thefirm could purchase a piece of machinery rather than hiring the worker.3.a. Suppose that a firm must pay an annual franchise fee, which is a fixed sum, independent of whether it produces any output. How does this tax aff ect the firm’s fixed, marginal, and average costs?Total cost, TC , is equal to fixed cost, FC , plus variable cost, VC . Fixed costs do not vary with thequantity of output. Because the franchise fee, FF , is a fixed sum, the firm’s fixed costs increaseby this fee. Thus, average cost, equal toFC VC Q +, and average fixed cost, equal to FC Q , increase by the average franchise fee FF Q. Note that the franchise fee does not affect average variable cost. Also, because marginal cost is the change in total cost with the production of anadditional unit and because the fee is constant, marginal cost is unchanged.3.b. Now suppose the firm is charged a tax that is proportional to the number of items it produces. Ag ain, how does this tax affect the firm’s fixed, marginal, and average costs?Let t equal the per unit tax. When a tax is imposed on each unit produced, variable costsincrease by tQ . Average variable costs increase by t , and because fixed costs are constant,average (total) costs also increase by t . Further, because total cost increases by t with eachadditional unit, marginal costs increase by t .4. A recent issue of Business Week reported the following:During the recent auto sales slump, GM, Ford, and Chrysler decidedit was cheaper to sell cars to rental companies at a loss than to lay offworkers. That’s because closing and reopening plants is expensive,partly because the auto makers’ current union contracts obligatethem to pay many wor kers even if they’re not working.When the article discusses selling cars “at a loss,” is it referring to accountingprofit or economic profit? How will the two differ in this case? Explainbriefly.When the article refers to the car companies selling at a loss, it is referring to accounting profit.The article is stating that the price obtained for the sale of the cars to the rental companies was less than their accounting cost. Economic profit would be measured by the difference of theprice with the opportunity cost of the cars. This opportunity cost represents the market valueof all the inputs used by the companies to produce the cars. The article mentions that the carcompanies must pay workers even if they are not working (and thus producing cars). Thisimplies that the wages paid to these workers are sunk and are thus not part of the opportunitycost of production. On the other hand, the wages would still be included in the accountingcosts. These accounting costs would then be higher than the opportunity costs and wouldmake the accounting profit lower than the economic profit.5. A chair manufacturer hires its assembly-line labor for $22 an hour and calculates that the rental cost of its machinery is $110 per hour. Suppose that a chair can be produced using 4 hours of labor or machinery in any combination. If the firm is currently using 3 hours of labor for each hour of machine time, is it minimizing its costs of production? If so, why? If not, how can it improve the situation?If the firm can produce one chair with either four hours of labor or four hours of capital,machinery, or any combination, then the isoquant is a straight line with a slope of -1 andintercept at K = 4 and L = 4, as depicted in Figure 7.5.The isocost line, TC = 22L + 110K has a slope of -=-2211002. when plotted with capital on the vertical axis and has intercepts at K TC =110 and L TC =22. The cost minimizing point is a corner solution, where L = 4 and K = 0. At that point, total cost is $88.6. Suppose the economy takes a downturn, and that labor costs fall by 50 percent and are expected to stay at that level for a long time. Show graphically how this change in the relative price of labor and capital affects the firm’s expansion path.Figure 7.6 shows a family of isoquants and two isocost curves. Units of capital are on the verticalaxis and units of labor are on the horizontal axis. (Note: In drawing this figure we have assumedthat the production function underlying the isoquants exhibits constant returns to scale, resultingin linear expansion paths. However, the results do not depend on this assumption.)If the price of labor decreases while the price of capital is constant, the isocost curve pivotsoutward around its intersection with the capital axis. Because the expansion path is the set ofpoints where the MRTS is equal to the ratio of prices, as the isocost curves pivot outward, theexpansion path pivots toward the labor axis. As the price of labor falls relative to capital, thefirm uses more labor as output increases.business when costs are cheaper and discourage off-peak business when costs are higher.Do you follow the consultant’s advice? Discuss.The consultant does not understand the definition of average cost. Encouraging ridership always decreases average costs, peak or off-peak. If ridership falls to 10, costs climb to $3.00 per rider. Further, during rush hour, the buses are full. How could more people get on? Instead, encourage passengers to switch from peak to off-peak times, for example, by charging higher prices during peak periods.MC 2 is the marginal cost of refining distillate up to the capacity constraint, Q 2. The shape of thetotal marginal cost curve is horizontal up to the lower capacity constraint. If the capacityconstraint of the distilling unit is lower than that of the hydrocracking unit, MC T is vertical at Q 1.If the capacity constraint of the hydrocracking unit is lower than that of the distilling unit, MC T isvertical at Q 2.9. You manage a plant that mass produces engines by teams of workers using assembly machines. The technology is summarized by the production function.Q 4 KLwhere Q is the number of engines per week, K is the number of assembly machines, and L is the number of labor teams. Each assembly machine rents for r = $12,000 per week and each team costs w = $3,000 per week. Engine costs are given by the cost of labor teams and machines, plus $2,000 per engine for raw materials. Your plant has a fixed installation of 10 assembly machines as part of its design.a. What is the cost function for your plant — namely, how much would it cost to produce Qengines? What are average and marginal costs for producing Q engines? How do average costs vary with output?K is fixed at 10. The short-run production function then becomes Q = 40 L. This implies that for any level of output Q, the number of labor teams hired will be L = Q / 40. The total cost function is thusgiven by the sum of the costs of capital, labor, and raw materials:TC(Q) = rK + wL + 2000Q = (12,000)(10) + (3,000)(Q/40) + 2,000 Q= 120,000 + 2,075QThe average cost function is then given by:AC(Q) = TC(Q)/Q = 120,000/Q + 2,075and the marginal cost function is given by:∂ TC(Q) / ∂ Q = 2,075Marginal costs are constant and average costs will decrease as quantity increases (due to the fixed cost of capital).b. How many teams are required to producing 80 engines? What is the average cost perengine?To produce Q = 80 engines we need L = Q/40 labor teams or L = 2. Average costs are given byAC(Q) = 120,000/Q + 2,075or AC = 3575 c. You are asked to make recommendations for the design of a new production facility. Whatwould you suggest? In particular, what capital/labor (K/L) ratio should the new plant accommodate? If lower average cost were your only criterion, should you suggest that the new plant have more production capacity or less production capacity that the plant you currently manage?We no longer assume that K is fixed at 10. We need to find the combination of K and L which minimizes costs at any level of output Q. The cost-minimization rule is given byMP r =MP w .KLTo find the marginal product of capital, observe that increasing K by 1 unit increases Q by 4L, so MP K = 4L. Similarly, observe that increasing L by 1 unit increases Q by 4K, so MP L = 4K. (Mathematically, MP K = ∆Q /∆K = 4L and MP L = ∆Q /∆L = 4K.) Using these formulas in the cost-minimization rule, we obtain:4L/r = 4K/w or K / L = w / r = 3,000 / 12,000 = 1/4The new plant should accommodate a capital to labor ratio of 1 to 4.The firm’s capital -labor ratio is currently 10/2 or 5. To reduce average cost, the firm should either use more labor and less capital to produce the same output or it should hire more labor and increase output.*10. A computer company’s cost function, which relates its average cost of product ion AC to its cumulative output in thousands of computers CQ and its plant size in terms of thousands of computers produced per year Q, within the production range of 10,000 to 50,000 computers is given byAC = 10 - 0.1CQ + 0.3Q.a. Is there a learning curve effect?The learning curve describes the relationship between the cumulative output and the inputsrequired to produce a unit of output. Average cost measures the input requirements per unit ofoutput. Learning curve effects exist if average cost falls with increases in cumulative output.Here, average cost decreases as cumulative output, CQ, increases. Therefore, there are learningcurve effects.b. Are there increasing or decreasing returns to scale?To measure scale economies, calculate the elasticity of total cost, TC, with respect to output, Q:ETCTCQQTCTCQMCACC ===∆∆∆∆.If this elasticity is greater (less) than one, then there are decreasing (increasing) returns to scale, because total costs are rising faster (slower) than output. From average cost we can calculate total and marginal cost:TC = Q(AC) = 10Q - (0.1)(CQ)(Q) + 0.3Q2, thereforeMCdTCdQCQ Q ==-+100106...Because marginal cost is greater than average cost (because 0.6Q > 0.3Q), the elasticity, EC, is greater than one; there are decreasing returns to scale. The production process exhibits a learningeffect and decreasing returns to scale.c. During its existence, the firm has produced a total of 40,000 computers and is producing 10,000computers this year. Next year it plans to increase its production to 12,000 computers. Will its average cost of production increase or decrease? Explain.First, calculate average cost this year:AC1= 10 - 0.1CQ + 0.3Q = 10 - (0.1)(40) + (0.3)(10) = 9.Second, calculate the average cost next year:AC2= 10 - (0.1)(50) + (0.3)(12) = 8.6.(Note: Cumulative output has increased from 40,000 to 50,000.) The average cost will decreasebecause of the learning effect.11. The short-run cost function of a company is given by the equation C = 190 + 53Q, where C is the total cost and Q is the total quantity of output, both measured in tens of thousands.a. What is the company’s fixed cost?When Q = 0, C = 190 (or $1,900,000). Therefore, fixed cost is equal to 190 (or $1,900,000).b. If the company produced 100,000 units of goods, what is its average variable cost?With 100,000 units, Q= 10. Variable cost is 53Q= (53)(10) = 530 (or $5,300,000). Averagevariable cost is TVCQ==$530$53.10c. What is its marginal cost per unit produced?With constant average variable cost, marginal cost is equal to average variable cost, $53.d. What is its average fixed cost?At Q = 10, average fixed cost is TFCQ==$190$1910.e. Suppose the company borrows money and expands its factory. Its fixed cost rises by $50,000,but its variable cost falls to $45,000 per 10,000 units. The cost of interest (I) also enters into the equation. Each one-point increase in the interest rate raises costs by $30,000. Write the new cost equation.Fixed cost changes from 190 to 195. Variable cost decreases from 53 to 45. Fixed cost alsoincludes interest charges: 3I . The cost equation isC = 195 + 45Q + 3I .*12. Suppose the long-run total cost function for an industry is given by the cubic equation TC = a + bQ + cQ 2 + dQ 3. Show (using calculus) that this total cost function is consistent with a U-shaped average cost curve for at least some values of a, b, c, d.To show that the cubic cost equation implies a U -shaped average cost curve, we use algebra,calculus, and economic reasoning to place sign restrictions on the parameters of the equation.These techniques are illustrated by the example below.First, if output is equal to zero, then TC = a , where a represents fixed costs. In the short run,fixed costs are positive, a > 0, but in the long run, where all inputs are variable a = 0. Therefore,we restrict a to be zero.Next, we know that average cost must be positive. Dividing TC by Q:AC = b + cQ + dQ 2.This equation is simply a quadratic function. When graphed, it has two basic shapes: a U shapeand a hill shape. We want the U shape, i.e., a curve with a minimum (minimum average cost),rather than a hill shape with a maximum.To the left of the minimum, the slope should be negative (downward sloping). At the minimum,the slope should be zero, and to the right of the minimum the slope should be positive (upwardsloping). The first derivative of the average cost curve with respect to Q must be equal to zero atthe minimum. For a U -shaped AC curve, the second derivative of the average cost curve must bepositive.The first derivative is c + 2dQ ; the second derivative is 2d . If the second derivative is to bepositive, then d > 0. If the first derivative is equal to zero, then solving for c as a function of Qand d yields: c = -2dQ . If d and Q are both positive, then c must be negative: c < 0.To restrict b , we know that at its minimum, average cost must be positive. The minimum occurswhen c + 2dQ = 0. We solve for Q as a function of c and d : Q c=->0. Next, substitutingthis value for Q into our expression for average cost, and simplifying the equation:2222⎪⎪⎭⎫ ⎝⎛-⎪⎪⎭⎫ ⎝⎛-++=++=d c d c d c b dQ cQ b AC , orAC b b b c d cd cd c d c d =-=-+=->+2222223362660. implying b c d >26. Because c 2and d > 0, b must be positive.In summary, for U -shaped long-run average cost curves, a must be zero, b and d must be positive, cmust be negative, and 4db > c 2. However, the conditions do not insure that marginal cost is positive.To insure that marginal cost has a U shape and that its minimum is positive, using the sameprocedure, i.e., solving for Q at minimum marginal cost -c d /,3 and substituting into theexpression for marginal cost b + 2cQ + 3dQ 2, we find that c 2 must be less than 3bd . Notice thatparameter values that satisfy this condition also satisfy 4db > c 2, but not the reverse.where a, b, and c are positive. Is this total cost function consistent with the presence of economies or diseconomies of scale? With economies or diseconomies of scope?There are two types of scale economies to consider: multiproduct economies of scale and product-specific returns to scale. From Section 7.5 we know that multiproduct economies of scalefor the two-product case, S H,S , are()()()()()S H S H MC S MC H S H TC S +=, , where MC H is the marginal cost of producing hardware and MC S is the marginal cost of producingsoftware. The product-specific returns to scale are:()()()()H H MC H S TC S H TC S ,0 , -= and ()()()()S S MC S H TC S H TC S 0, , -= where TC (0,S ) implies no hardware production and TC (H ,0) implies no software production. Weknow that the marginal cost of an input is the slope of the total cost with respect to that input.Since()(),S cH b aH bS H cS a TC -+=+-=we have MC H = a - cS and MC S = b - cH .Substituting these expressions into our formulas for S H,S , S H , and S S :()()cH b S cS a H cHS bS aH S S H -+--+=, or S aH bS cHS H S ,=+-+->1, because cHS > 0. Also, ()()cS a H bS cHS bS aH S H ---+=, or()()()()1=--=--=cS a cS a cS a H cHS aH S H and similarly ()().1=---+=cH b S aH cHS bS aH S S There are multiproduct economies of scale, S H,S > 1, but constant product-specific returns to scale,S H = S C = 1.Economies of scope exist if S C > 0, where (from equation (7.8) in the text):()()()()S H TC S H TC S TC H TC S c , , ,0 0, -+=, or, ()()S H TC cHS bS aH bS aH S c , -+-+=, or ().0, >=S H TC cHS S c Because cHS and TC are both positive, there are economies of scope.CHAPTER 8PROFIT MAXIMIZATION AND COMPETITIVE SUPPLYAs the title implies, this chapter covers two interrelated topics: a consideration of the behavioral incentives of the profit-maximizing firm and an examination of the interaction of these firms in a competitive market. The chapter begins with a discussion of whether firms maximize profits and ends with a discussion of the criteria for a competitive market, including an introduction to contestable markets. Exercises (1), (2), and (4) rely on data discussed in the text, while Exercises (3), (6), and (7) focus on the determination of the firm’s profit -maximizing quantity. Exercises (5), (8), and (9) consider the influence of taxes on firms’ output in a competitive market.S ections 8.2 through 8.4 derive the firm’s supply curve. Although total revenue is easily understood, you will need to show why average revenue may be represented by the demand curve. Demand and average revenue will be used interchangeably in Chapters 10 and 11. When presented with a problem involving the derivation of marginal revenue, some students will substitute Q , instead of P , in the expression for total revenue. This leads to revenue as a function of price. Stress that when they are given a demand curve in these applications they should first solve for price as a function of quantity. The origin of this confusion could lie in the popular notion that the firm determines the profit-maximizing price instead of the profit-maximizing quantity. Emphasize the importance of quantity, for example, when discussing why deviations from the profit-maximizing quantity lead to a decrease in profit (see Figure 8.3). Using the solutions to the exercises, emphasize that, for a linear demand curve, the slope of the marginal revenue curve is twice the slope of the demand curve.Other sources of confusion arise during analysis of firms’ supply curves. Stress that, as a primary rule, the firm should choose a quantity such that marginal revenue is equal to marginal cost. In this chapter, we can simplify this rule: for a firm facing a perfectly elastic demand curve, price is equal to marginal revenue. Stress that the rule for the competitive firm is a special case. Although some students will understand references to second-order conditions, expect to be asked why q 0 in Figure 8.3 is not profit maximizing, although MR = MC . Two additional points warrant careful explanation: 1) why the firm would remain in business if the firm sustains a loss in the short run, and 2) that maximizing profit is the same as minimizing loss.Although the summation of firm supply curves into a market supply curve is easy, the analysis of long-run competitive equilibrium is difficult. Show that long-run equilibrium relies on profit maximization by firms. Accompanying the rule that price must be greater than average variable cost in the short run, there is the assumption of free entry and exit. This leads to the statement that price must equal long-run average cost, LAC, as no firm may make an economic profit. The rule that price must equal long-run marginal cost, LMC , is the second equilibrium condition. Therefore, because LAC = LMC at minimum LAC , price is equal to minimum LAC in the long-run equilibrium. This result will be reconsidered in Chapter 12 in the discussion of equilibrium for a monopolistically competitive firm. When discussing the attainment of equilibrium in constant, increasing, and。
(NEW)平狄克《微观经济学》(第7版)课后习题详解
目 录第1篇 导论：市场和价格第1章 绪 论1.1 课后复习题详解1.2 课后练习题详解第2章 供给和需求的基本原理2.1 课后复习题详解2.2 课后练习题详解第2篇 生产者、消费者以及竞争性市场第3章 消费者行为3.1 课后复习题详解3.2 课后练习题详解第4章 个人需求和市场需求4.1 课后复习题详解4.2 课后练习题详解第4章附录 需求理论——一种数学的处理方法课后练习题详解第5章 不确定性与消费者行为5.1 课后复习题详解5.2 课后练习题详解第6章 生 产6.1 课后复习题详解6.2 课后练习题详解第7章 生产成本7.1 课后复习题详解7.2 课后练习题详解第7章附录 生产与成本理论——一种数学的处理方法课后练习题详解第8章 利润最大化和竞争性供给8.1 课后复习题详解8.2 课后练习题详解第9章 竞争性市场分析9.1 课后复习题详解9.2 课后练习题详解第3篇 市场结构和竞争策略第10章 市场势力：垄断与买方垄断10.1 课后复习题详解10.2 课后练习题详解第11章 有市场势力的定价11.1 课后复习题详解11.2 课后练习题详解第11章附录 联合厂商的内部转移定价课后练习题详解第12章 垄断竞争和寡头垄断12.1 课后复习题详解12.2 课后练习题详解第13章 博弈论和竞争策略13.1 课后复习题详解13.2 课后练习题详解第14章 投入要素市场14.1 课后复习题详解14.2 课后练习题详解第15章 投资、时间及资本市场15.1 课后复习题详解15.2 课后练习题详解第4篇 信息、市场失灵以及政府的角色第16章 一般均衡与经济效率16.1 课后复习题详解16.2 课后练习题详解第17章 信息不对称市场17.1 课后复习题详解17.2 课后练习题详解第18章 外部性与公共品18.1 课后复习题详解18.2 课后练习题详解附录：指定平狄克《微观经济学》教材为考研参考书目的院校列表第1篇 导论：市场和价格第1章 绪 论1.1 课后复习题详解1．人们常说，一个好的理论是可以用经验研究和实证研究来加以证伪的。
平狄克微观经济学答案——第6章生产
第六章生产第六章是三章有关供给理论内容中的第一部分。
复习或总结学过的需求理论对总体观察竞争性供给理论是有帮助的。
复习有助于找出需求理论和供给理论的相似之处。
学生们通常都认为供给理论比较容易掌握，因为它们不是很抽象，而且对内容比较熟悉。
学习它可以有助于帮助学生在复习的时候更好的理解需求理论。
在本章中，重点要多花时间和精力掌握一些概念，因为它们是下两章的基础。
生产函数的内容并不难，但是有时候数学和图表表达式会引起疑惑。
多做例题会有所帮助的。
在做生产函数坐标图时，纵轴为产量，横轴为一种生产要素投入，表示生产函数是生产规划的范围，即无论投入量在任何水平的最高产量。
技术效率也在供给理论中加以了讨论。
在任何时间你都可以引入讨论提高生产效率的重要性并通过讨论得出内容。
课本中例1和例2都适合做讨论。
由生产函数的坐标图很自然的展开对边际产量和报酬递减的讨论。
强调报酬递减存在是因为一些生产要素已经被定义为固定不变，而且报酬递减并不代表报酬为负的。
如果你还没有讨论边际效用，那么是时候让学生知道平均和边际的不同了。
例如引导学生先从对考试的平均和边际成绩之间的关系来进入讨论。
如果他们上学期期中成绩高于平均成绩的话，这会提高他们的平均水平。
虽然等产量线在本章一开始就已给出定义，但是却是在本章的后面部分才用以分析。
在进行对等产量线讨论的过程中可以借助学生对无差异曲线的理解。
]并指出，等产量线是生产函数三维空间的二维表示。
本章最后部分的重点是边际技术替代率与规模报酬。
做尽可能多具体的例题用来帮助解释这两个重要的内容。
例6.3和6.4有助于加强理MRTS和规模报酬。
复习题1、什么是生产函数？短期生产函数和长期生产函数有何区别？生产函数代表企业的投入转换成为产出。
我们关注的是厂商的产出，以及生产要素的在一个生产周期内的总投入，例如：劳动力、资本以及原材料。
短期内一个或多个生产要素不会发生变化，随着时间的推移，厂商变有机会对投入的要素进行调整。
平狄克《微观经济学》课后答案 3-4
CHAPTER 3CONSUMER BEHAVIORChapter 3 builds the foundation to derive the demand curve in Chapter 4. In order to understand demand theory, students must have a firm grasp of indifference curves, the marginal rate of substitution, the budget line, and optimal consumer choice. Utility theory may be discussed independently from consumer choice. Many students find utility functions to be a more abstract concept than preference relationships. However, if you plan to discuss uncertainty in Chapter 5, you will need to cover marginal utility. Even if you cover utility theory only briefly, make sure students are comfortable with the term utility because it appears frequently in Chapter 4.When introducing indifference curves, stress that physical quantities are represented on the two axes. After discussing supply and demand, students may think that price should be on the vertical axis. To develop indifference curves, start with any point in the Cartesian plane and ask for points that are more (and less) preferred. This will divide the plane into four quadrants. Then ask between which points they will be indifferent. Once students grasp the concept of preference points, introduce the notion of a “preference hill.” Using the example of a topographical map or a well-drawn three dimensional figure, point out that a three-dimensional figure is being collapsed into two dimensions.The marginal rate of substitution, MRS , is confusing to students. Some confuse the MRS with the ratio of the two quantities. If this is the case, point out that the slope is equal to the ratio of the rise, ∆Y, and the run, ∆X . This ratio is equal to the ratio of the intercepts of a line just tangent to the indifference curve. As we move along a convex indifference curve, these intercepts and the MRS change. Another problem is the terminology “of X for Y .” This is confusing because we are not substituting “X for Y ,” but Y for one unit of X . Exercise (6) discusses this point, but you may want to offer other exercises to stress it.1. What does transitivity of preferences mean?Transitivity of preferences implies that if someone prefers A to B and prefers B to C , then he orshe prefers A to C .satisfaction. This trading continues until the highest level of satisfaction is achieved.6. Explain why consumers are likely to be worse off when a product that they consume is rationed.If the maximum quantity of a good is fixed by decree and desired quantities are not available forpurchase, then there is no guarantee that the highest level of satisfaction can be achieved. Theconsumer will not be able to give up the consumption of other goods in order to obtain more of therationed good. Only if the amount rationed is greater than the desired level of consumption canthe consumer still maximize satisfaction without constraint. (Note: rationing may imply ahigher level of social welfare because of equity or fairness considerations across consumers.)7. Upon merging with West Germany’s economy, East German consumers indicated a preference for Mercedes-Benz automobiles over Volkswagen automobiles. However, when they converted their savings into deutsche marks, they flocked to Volkswagen dealerships. How can you explain this apparent paradox?Three assumptions are required to address this question: 1) that a Mercedes costs more than aVolkswagen; 2) that the East German consumers’ utility function comprises two goods,automobiles and all other goods evaluated in deutsche marks; and 3) that East Germans haveincomes. Based on these assumptions, we can surmise that while once-East German consumersmay prefer a Mercedes to a Volkswagen, they either cannot afford a Mercedes or they prefer abundle of other goods plus a Volkswagen to a Mercedes alone.8. Describe the equal marginal principle. Explain why this principle may not hold if increasing marginal utility is associated with the consumption of one or both goods.The equal marginal principle states that the ratio of the marginal utility to price must be equalacross all goods to obtain maximum satisfaction. This explanation follows from the same logicexamined in Review Question 5. Utility maximization is achieved when the budget is allocatedso that the marginal utility per dollar of expenditure is the same for each good.If marginal utility is increasing, the consumer maximizes satisfaction by consuming ever largeramounts of the good. Thus, the consumer would spend all income on one good, assuming aconstant price, resulting in a corner solution. With a corner solution, the equal marginalprinciple cannot hold.9. What is the difference between ordinal utility and cardinal utility? Explain why the assumption of cardinal utility is not needed in order to rank consumer choices.Ordinal utility implies an ordering among alternatives without regard for intensity of preference.For example, the consumer’s first choice is preferred to their second choice. Cardinal utilityimplies that the intensity of preferences may be quantified. An ordinal ranking is all that isneeded to rank consumer choices. It is not necessary to know how intensely a consumer prefersbasket A over basket B; it is enough to know that A is preferred to B.10. The price of computers has fallen substantially over the past two decades. Use this drop in price to explain why the Consumer Price Index is likely to substantially understate the cost-of-living index for individuals who use computers intensively.The consumer price index measures the changes in the weighted average of the prices of thebundle of goods purchased by consumers. The weights equal the share of consumer's expenditureson all of the goods in the bundle. A base year is chosen, and the weights for that year are used tocompute the CPI in that and subsequent years. When the price of a good falls substantially then aconsumer will substitute towards that good, altering the share of that consumer's income spent oneach good. By using the base year's weights the CPI does not take into account that large pricechanges alter these expenditure shares, and so gives an inaccurate measure of changes in the costof living.For example, assume Fred spends 10% of his income on computers in 1970, and that Fred'sexpenditure shares in 1970 were used as the weights to calculate Fred's CPI in subsequent years.If Fred's demand for computers was inelastic, then reductions in the price of computers (relativeto other goods) would reduce the share of his income spent on computers. After 1970 a CPI thatused Fred's 1970 expenditure shares as weights would give a 10% weight to the falling price ofcomputers, even though Fred spent less that 10% of his income on computers. So long as theprices of other goods rose, or fell less than 10%, then the CPI gives too little weight to the changesin the prices of other goods, and understates the changes in Fred's cost of living.1. In this chapter, consumer preferences for various commodities did not change during the analysis. Yet in some situations, preferences do change as consumption occurs. Discuss why and how preferences might change over time with consumption of these two commodities:a. cigarettesThe assumption that preferences do not change is a reasonable one if choices are independentacross time. It does not hold, however, when “habit-forming” or addictive behavior is involved, asin the case of cigarettes: the consumption of cigarettes in one period influences their consumptionin the next period.b. dinner for the first time at a restaurant with a special cuisineWhile there may not be anything physically addictive in dining at new and different restaurants, one can become better informed about a particular restaurant. One may enjoy choosing more new and different restaurants, or one may be tired of choosing another new and different place to4.a.c. tothis graphically?, the quantity of butter by B, the Let Bill’s income be represented by Y, the price of butter by PB, and the quantity of margarine by M. Then the general form of the price of margarine by PMbudget constraint is:5.the their a.c. If both Smith and Jones pay the same prices for their refreshments, will their marginal rates ofsubstitution of alcoholic for nonalcoholic drinks be the same or different? Explain.In order to maximize utility, the consumer must consume quantities such that the MRS betweenany two commodities is equal to the ratio of prices. If Smith and Jones are rational consumers,their MRS must be equal because they face the same market prices. But because they havedifferent preferences, they will consume different amounts of the two goods, alcoholic andnonalcoholic. At those different levels, however, their MRS are equal.6. Anne is a frequent flyer whose fares are reduced (through coupon giveaways) by 25 percent after she flies 25,000 miles a year, and then by 50 percent after she flies 50,000 miles. Can you graph the budget line that Anne faces in making her flight plans for the year?In Figure 3.6, we plot miles flown, M , against all other goods, G , in dollars. The budgetconstraint is:Y = P M M + P G G , or.⎪⎪⎭⎫ ⎝⎛-=G M G P P M P Y G The slope of the budget line is -P P M G. In this case, the price of miles flown changes as the number of miles flown changes, so the budget curve is kinked at 25,000 and at 50,000 miles. Suppose P M is $1 per mile for less than or equal to 25,000 miles. Then P M = $0.75 for 25,000 < M ≥ 50,000 and P M = $0.50 for M > 50,000. Also, let P G = $1.00. Then the slope of the budget line from A to B is -1, the slope of the budget line from B to C is -0.75, and the slope of the budget line from B to D is -0.5.8. Suppose that Samantha and Jason both spend $24 per week on video and movie entertainment.U = 12 U = 24Food Clothing Food Clothing 1.0 12.0 1.0 24.01.5 8.02.0 12.02.0 6.03.0 8.012 = 1F + 3C , or ⎪⎪⎭⎝-=34.See Figure 3.10.a.c. What is the utility-maximizing choice of food and clothing? (Hint: Solve the problemgraphically.)The highest level of satisfaction occurs where the budget line is tangent to the highestindifference curve. In Figure 3.10.a this is at the point F = 6 and C = 2. To check this answer,note that it exhausts Jane’s income, 12 = 6P F + 2P C . Also, this bundle yields a satisfaction of 12,as (6)(2) = 12. See Figure 3.10.a.d. What is the marginal rate of substitution of food for clothing when utility is maximized?At the utility-maximizing level of consumption, the slope of the indifference curve is equal to theslope of the budget constraint. Since the MRS is equal to the negative slope of the indifferencecurve, the MRS in this problem is equal to one-third. Thus, Jane would be willing to give upone-third of a unit of clothing for one unit of food.e. Suppose that Jane buys 3 units of food and 3 units of clothing with her $12 budget. Would hermarginal rate of substitution of food for clothing be greater or less than 1/3? Explain.If Jane buys 3 units of food for $1.00 per unit and 3 units of clothing for $3.00 per unit, she wouldspend all her income. However, she would obtain a level of satisfaction of only 9, whichrepresents a sub-optimal choice. At this point, the MRS is greater than one-third, and thus, atthe prices she faces, she would welcome the opportunity to give up clothing to get more food. Sheis willing to trade clothing for food until her MRS is equal to the ratio of prices. See Figure3.10.c.Figure 3.10.c11. The utility that Meredith receives by consuming food F and clothing C is given by u(F,C) = FC. Suppose that Meredith’s income in 1990 is $1,200 and the prices of food and clothing are $1 per unit for each. However, by 1995 the price of food has increased to $2 and the price of clothing to $3. Let 100 represent the cost of living index for 1990. Calculate the ideal and the Laspeyres cost-of-living index for Meredith for 1995. (Hint: Meredith will spend equal amounts on food and clothing with these preferences.)Laspeyres IndexThe Laspeyres index represents how much more Meredith would have to spend in 1995 versus 1990 ifshe consumed the same amounts of food and clothing in 1995 as she did in 1990. That is, the Laspeyresindex for 1995 (L) is given by:L = 100 (Y ')/Ywhere Y’ represents the amount Meredith would spend at 1995 prices consuming the same amount offood and clothing as in 1990: Y ' = P 'F F + P 'C C = 2F + 3C, where F and C represent the amounts of foodand clothing consumed in 1990.We thus need to calculate F and C, which make up the bundle of food and clothing which maximizesMeredith’s utility given 1990 prices and her income in 1990. Use the hint to simplify the problem:Since she spends equal amounts on both goods, P F F = P C C. Or, you can derive this same equationmathematically: With this utility function, MU C = ∆U/∆C = F, and MU F = ∆U/∆F = C. To maximizeutility, Meredith chooses a consumption bundle such that MU F /MU C = P F /P C , which again yields P F F =P C C.From the budget constraint, we also know that:P F F +P C C = YCombining these two equations and substituting the values for the 1990 prices and income yields thesystem of equations:C = F and C + F = 1,200Solving these two equations, we find that:C = 600 and F = 600Therefore, the Laspeyres cost-of-living index is:L = 100(2F + 3C)/Y = 100[(2)(600) + (3)(600)]/1200 = 250Ideal IndexThe ideal index represents how much more Meredith would have to spend in 1995 versus 1990 if sheconsumed amounts of food and clothing in 1995 which would give her the same amount of utility as shehad in 1990. That is, the ideal index for 1995 (I) is given by:I = 100(Y'')/Y, where Y'' = P'F F + P'C C' = 2F' + 3C'where F' and C' are the amount of food and clothing which give Meredith the same utility as she had in1990. F' and C' must also be such that Meredith spends the least amount of money at 1995 prices toattain the 1990 utility level.The bundle (F',C') will be on the same indifference curve as (F,C) and the indifference curve at this point will be tangent to a budget line with slope -(P'F /P'C ), where P'F and P'C are the prices of food and clothing in 1995. Since Meredith spends equal amounts on the two goods, we know that 2F' = 3C'. Since this bundle lies on the same indifference curve as the bundle F = 600, C = 600, we also know that F'C' = (600)(600).Cslope 1P slope F C =-H K slope slope F C =-'H KFigure 3.11Solving for F' yields:F'[(2/3)F'] = 360,000 or F' =[(/),)]32360000 = 734.8From this, we obtain C':C' = (2/3)F' = (2/3)734.8 = 489.9We can now calculate the ideal index: I = 100(2F' + 3C')/Y = 100[2(734.8) + (3)(489.9)]/1200 = 244.9CHAPTER 4INDIVIDUAL AND MARKET DEMANDChapter 4 relies on two important ideas from Chapter 3: the influence of price and income changes on the budget line and optimal consumer choice. The chapter focuses on price changes, individual demand, market demand, demand elasticity, and consumer surplus. These concepts are crucial to understanding the application of demand and supply analysis in Chapter 9 as well as the discussion of market failure in Parts III and IV. Chapter 4 also discusses the derivation of the individual’s demand curve with a discussion of substitution and income effects. The analytical tools students learn in this chapter will be important for the discussion of factor supply and demand in Chapter 14.When discussing the derivation of demand, review how the budget curve pivots around an intercept as price changes and how optimal quantities change as the budget line pivots. Once students understand the effect of price changes on consumer choice, they can grasp the derivation of the price consumption path and the individual demand curve. Remind students that the price a consumer is willing to pay is a measure of the marginal benefit of consuming another unit.When covering the aggregation of individual demands, stress that this is equivalent to the summation of individual demand curves horizontally. Students might think that they can add linear demand functions, e.g., add Q P =-1 plus Q P =-23 to arrive at Q P =-35 or 223Q P =-. Students must be reminded, instead, to write the demand curve in inverse form, with price as a function of quantity, and then add. Thus, we add P = 1 - Q to P = 1 - 2Q to obtain P = 2 - 3Q .Price elasticity of demand and consumer surplus are referred to throughout the text, but the mathematics of price elasticity of demand is difficult for many students. Before discussing the algebra, encourage students to develop an intuitive grasp of elasticity as a measure of the sensitivity of the quantity demanded to changes in price.The easiest algebraic representation of elasticity is %%∆∆QP. As you expand on this expression, make sure thatstudents can distinguish between the slope of a line and an elasticity at each point. One effective teaching method is using a linear demand curve to show that while the slope is constant, the elasticity changes throughout the range of prices. The text relies on this relationship in the discussion of the monopolist’s determination of the profit-maximizing quantity in Chapter 10. The exercises given here are progressive in their difficulty, i.e., the last exercise is much harder than the first. Exercises (1) and (7) assume student understanding of demand elasticity, and a grasp of income elasticity is needed for Exercise (9).Although this chapter introduces consumer surplus, it is not extensively discussed until Chapter 9; producer surplus is covered in Chapter 8. If you postpone the discussion of consumer surplus, do not assign Exercise (4). Once students understand consumer surplus, they will find it to be an extremely useful tool. See Example 4.5.Section 4.2 discusses income and substitution effects. An understanding of these effects is aided by the discussion of normal and inferior goods. This is also a good time to reinforce the concept of relative prices, i.e., a decrease in the price of one good increases the relative price of the other good. Giffen goods, while infrequently encountered, provide a way to discuss the importance of income and substitution effects.Finally, there are other special topics in this chapter and its Appendix. An application of network externalities is given in Example 4.5. The first part of Section 4.6, “Empirical Estimation of Demand,” is straightforward, particularly if you have covered the forecasting section of Chapter 2. However, the l ast part, “The Form of the Demand Relationship,” is difficult for students who do not understand logarithms. The Appendix is intended for students with a background in calculus.1.How is an individual demand curve different from a market demand curve? Which curve is likely to be more price elastic? (Hint: Assume that there are no network externalities.)The market demand curve is the horizontal summation of the individual demand curves. Thegraph of market demand shows the relation between each price and the sum of individualquantities. Because price elasticities of demand may vary by individual, the price elasticity ofdemand is likely to be greater than some individual price elasticities and less than others.2.Is the demand for a particular brand of product, such as Head skis, likely to be more price elastic or price inelastic than the demand for the aggregate of all brands, such as downhill skis? Explain.Individual brands compete with other brands. If the two brands are similar, a small change inthe price of one good will encourage many consumers to switch to the other brand. Becausesubstitutes are readily available, the quantity response to a change in one brand’s price is moreelastic than the quantity response for all brands. Thus, the demand for Head skis is more elasticthan the demand for downhill skis.3.Tickets to a rock concert sell for $10. But at that price, the demand is substantially greater than the available number of tickets. Is the value or marginal benefit of an additional ticket greater than, less than, or equal to $10? How might you determine that value?If, at $10, demand exceeds supply, then consumers are willing to bid up the market price to a levelwhere the quantity demanded is equal to the quantity supplied. Since utility-maximizingconsumers must be willing to pay more than $10, then the marginal increase in satisfaction(value) is greater than $10. One way to determine the value of tickets would be to auction off ablock of tickets. The highest bid would determine the value of the tickets.4.Suppose a person allocates a given budget between two goods, food and clothing. If food is an inferior good, can you tell whether clothing is inferior or normal? Explain.If an individual consumes only food and clothing, then any increase in income must be spent oneither food or clothing (Hint: we assume there are no savings). If food is an inferior good, then,as income increases, consumption falls. With constant prices, the extra income not spent on foodmust be spent on clothing. Therefore, as income increases, more is spent on clothing, i.e. clothingis a normal good.5. Which of the following combinations of goods are complements and which are substitutes? Could they be either in different circumstances? Discuss.a. a mathematics class and an economics classIf the math class and the economics class do not conflict in scheduling, then the classes could beeither complements or substitutes. The math class may illuminate economics, and theeconomics class can motivate mathematics. If the classes conflict, they are substitutes.b. tennis balls and a tennis racketTennis balls and a tennis racket are both needed to play a game of tennis, thus they arecomplements.c. steak and lobsterFoods can both complement and substitute for each other. Steak and lobster can compete, i.e., besubstitutes, when they are listed as separate items on a menu. However, they can also functionas complements because they are often served together.d. a plane trip and a train trip to the same destinationTwo modes of transportation between the same two points are substitutes for one another.e. bacon and eggsBacon and eggs are often eaten together and are, therefore, complementary goods. Byconsidering them in relation to something else, such as pancakes, bacon and eggs can function assubstitutes.6.Which of the following events would cause a movement along the demand curve for U.S.-produced clothing, and which would cause a shift in the demand curve?a. the removal of quotas on the importation of foreign clothesThe removal of quotas will shift the demand curve inward for domestically-produced clothes,because foreign-produced goods are substitutes for domestically-produced goods. Both theequilibrium price and quantity will fall as foreign clothes are traded in a free marketenvironment.b. an increase in the income of U.S. citizensWhen income rises, expenditures on normal goods such as clothing increase, causing the demandcurve to shift out. The equilibrium quantity and price will increase.c. a cut in the industry’s costs of producing domestic clothes that is passed on to the market inthe form of lower clothing pricesA cut in an industry’s costs will shift the supply curve out. The equilibrium price an d quantitywill increase.7. For which of the following goods is a price increase likely to lead to a substantial income (as well as substitution) effect?a. saltSmall income effect, small substitution effect: The amount of income that is spent on salt isrelatively small, but since there are few substitutes for salt, consumers will not readily substituteaway from it. As the price of salt rises, real income will fall only slightly, thus leading to a smalldecline in consumption.b. housingLarge income effect, no substitution effect: The amount of income spent on housing is relativelylarge for most consumers. If the price of housing were to rise, real income would be reducedsubstantially, thereby reducing the consumption of all other goods. However, consumers wouldfind it impossible to substitute for housing, in general.c. theater ticketsSmall income effect, large substitution effect: The amount of income that is spent on theatertickets is relatively small, but consumers can substitute away from the theater tickets by choosingother forms of entertainment (e.g., television and movies). As the price of theater tickets rises,real income will fall only slightly, thus leading to a small decline in consumption.d. foodLarge income effect, no substitution effect: As with housing, the amount of income spent on food isrelatively large for most consumers. Price increases for food will reduce real incomesubstantially, thereby reducing the consumption of all other commodities. Although consumerscan substitute out of particular foods, they cannot substitute out of food in general.8. Suppose that the average household in a state consumes 500 gallons of gasoline per year. A 10-cent gasoline tax is introduced, coupled with a $50 annual tax rebate per household. Will the household be better or worse off after the new program is introduced?If the household does not change its consumption of gasoline, it will be unaffected by thetax-rebate program. It still gets 500 gallons of gasoline. To the extent that the householdreduces its gas consumption through substitution, it must be better off.9. Which of the following three groups is likely to have the most, and which the least, price-elastic demand for membership in the Association of Business Economists?a. studentsThe major difference among the groups is the level of income. We know that if the consumptionof a good constitutes a large percentage of an individual’s income, then the demand for the goodwill be relatively elastic. If we assume that a membership in the Association of BusinessEconomists is likely to be a large expenditure for students, we may conclude that the demand willbe relatively elastic for this group.b. junior executivesThe level of income for junior executives will be larger than that of students, but smaller thanthat of senior executives. Therefore, the demand for a membership for this group will be lesselastic than that of the students but more elastic than that of the senior executives.c. senior executivesThe high earnings among senior executives will result in a relatively inelastic demand formembership.1. The ACME corporation determines that at current prices the demand for its computer chips has a price elasticity of -2 in the short run, while the price elasticity for its disk drives is -1.a. If the corporation decides to raise the price of both products by 10 percent, what will happento its sales? To its sales revenue?We know the formula for the elasticity of demand is:EQP P=%%∆∆.For computer chips, EP= -2, so a 10 percent increase in price will reduce the quantity sold by 20percent. For disk drives, EP= -1, so a 10 percent increase in price will reduce sales by 10 percent.Sales revenue is equal to price times quantity sold. Let TR1 = P1Q1be revenue before the pricechange and TR2 = P2Q2be revenue after the price change.For computer chips:∆TR cc = P2Q2 - P1Q1∆TR cc= (1.1P1 )(0.8Q1 ) - P1Q1 = -0.12P1Q1, or a 12 percent decline.For disk drives:∆TR dd = P2Q2 - P1Q1∆TR dd = (1.1P1 )(0.9Q1 ) - P1Q1 = -0.01P1Q1, or a 1 percent decline.Therefore, sales revenue from computer chips decreases substantially, -12 percent, while the salesrevenue from disk drives is almost unchanged, -1 percent.b. Can you tell from the available information which product will generate the most revenue forthe firm? If yes, why? If not, what additional information would you need?No. Although we know the responsiveness of demand to changes in price, we need to know bothquantities and prices of the products to determine total sales revenue.2. Refer to Example 4.3 on the aggregate demand for wheat. From 1981 to 1990, domestic demand grew in response to growth in U.S. income levels. As a rough approximation, the domestic demand curve in 1990 was QDD= 1200 - 55P. Export demand, however, remained about the same, due to。
平狄克《微观经济学》课后答案 10
CHAPTER 10MARKET POWER: MONOPOLY AND MONOPSONYIn most textbooks, the title of this chapter would be “Monopoly,” and monopsony would be found in a section of the chapter on factor markets. This text, however, gives monopoly and monopsony parallel treatment. There is an initial discussion of monopoly (Sections 1-4), a briefer discussion of monopsony (Section 5), and a joint consideration of the two (Section 6). Exercises (1) through (5) focus on the monopolist’s determination of a profit-maximizing output. Exercises (6) and (7) explore the multiplant firm. Exercise (8) examines the decision in the U.S. antitrust case against Alcoa. Exercises (10) and (12) examine monopsony power. Exercises (9), (13),(14), and (15) focus on price regulation.Although previous chapters have presented the rule for profit maximization, you should briefly review marginal revenue and price elasticity of demand through a careful derivation of Equation 10.1. A discussion of the derivation of Equation 10.1 will elucidate the geometry of Figure 10.3: illustrate that because the monopolist chooses a quantity such that marginal revenue is positive, demand at that quantity is elastic. Equation 10.1 also leads directly to the Lerner Index in Section 10.2. This pro vides fruitful ground for a discussion of a monopolist’s market power. For example, if E d is large (e.g., because of close substitutes), then (1) the demand curve is flat, (2) the marginal revenue curve is flat (although steeper than the demand curve), and (3) the monopolist has little power to raise price above marginal cost. To reinforce these points, introduce a non-linear demand curve by, for example, showing the location of the marginal revenue curve for a unit-elastic demand curve. Once this concept has been clearly presented, the discussion of the effect of an excise tax on a monopolist with non-linear demand (Figure 10.5) will not seem out of place.The social response to market power provides a good topic for class discussion, and this topic can be introduced by comparing the deadweight loss with the analysis of market intervention given in Chapter 9. For example, compare Figure 10.9 with Figure 9.6. Because Exercises (9), (13), and (15) involve “kinked marginal revenue curves,” you should pres ent Figure 10.10 if you plan to assign those problems. Although Figure 10.10 is complicated, exposure to it here will help when it reappears in Chapter 12.1. When marginal cost is greater than marginal revenue, the incremental cost of the last unit produced is greater than incremental revenue. The firm would increase its profit by not producing the last unit. It should continue to reduce production, thereby decreasing marginal cost and increasing marginal revenue, until marginal cost is equal to marginal revenue.2. We can show that this measure of market power is equal to the negative inverse of the price elasticity of demand.P MC P E D-=-1 The equation implies that, as the elasticity increases (demand becomes more elastic), the inverse of elasticity decreases and the measure of market power decreases. Therefore, as elasticity increases (decreases), the firm has less (more) power to increase price above marginal cost.3. The monopolist’s output decision depends not only on mar ginal cost, but also on the demand curve. Shifts in demand do not trace out a series of prices and quantities that we can identify as the supply curve for the firm. Instead, shifts in demand lead to changes in price, output, or both. Thus, there is no one-to-one correspondence between the price and the seller’s quantity; therefore, a monopolized market lacks a supply curve.4. The degree of monopoly power or market power enjoyed by a firm depends on the elasticity of the demand curve that it faces. As the elasticity of demand increases, i.e., as the demand curve becomes flatter, the inverse of the elasticity approaches zero and the monopoly power of the firm decreases. Thus, if the firm’s demand curve has any elasticity less than infinity, the firm has some monopoly power.5. The firm’s exploitation of its monopoly power depends on how easy it is for other firms to enter the industry. There are several barriers to entry, including exclusive rights (e.g., patents, copyrights, and licenses) and economies of scale. These two barriers to entry are the most common. Exclusive rights are legally granted property rights to produce or distribute a good or service. Positive economies of scale lead to “natural monopolies” because the largest producer can charge a lower price, driving competition from the market. For example, in the production of aluminum, there is evidence to suggest that there are scale economies in the conversion of bauxite to alumina. (See U.S. v. Aluminum Company of America , 148 F.2d 416 [1945], discussed in Exercise 7, below.)6. Three factors determine the firm’s elasticity of demand: (1) the elasticity of market demand, (2) the number of firms in the market, and (3) interaction among the firms in the market. The elasticity of market demand dependson the uniqueness of the product, i.e., how easy it is for consumers to substitute away from the product. As the number of firms in the market increases, the demand elasticity facing each firm increases because customers may shift to the fir m’s competitors. The number of firms in the market is determined by how easy it is to enter the industry (the height of barriers to entry). Finally, the ability to raise the price above marginal cost depends on how other firms react to the firm’s price c hanges. If other firms match price changes, customers will have little incentive to switch to another supplier.7. When the firm exploits its monopoly power to raise the price above marginal cost, consumers buy less at the higher price. Consumers enjoy less surplus, the difference between the price they are willing to pay and the market price on each unit consumed. Some of the lost consumer surplus is not captured by the seller and is a deadweight loss to society. Therefore, if the gains to producers were redistributed to consumers, society would still suffer the deadweight loss.8. By restricting price below the monopolist’s profit-maximizing price, the government can change the shape of the firm’s marginal revenue, MR, curve. When a price ceiling is imposed, MR is equal to the price ceiling for all quantities lower than the quantity demanded at the price ceiling. If the government wants to maximize output, it should set a price equal to marginal cost. Prices below this level induce the firm to decrease production, assuming the marginal cost curve is upward sloping. The regulator’s problem is to determine the shape of the monopolist’s marginal cost curve. This task is difficult given the monopolist’s incentive to hide or distort this information.9. The marginal expenditure is the change in the total expenditure as the purchased quantity changes. For a firm competing with many firms for inputs, the marginal expenditure is equal to the average expenditure (price). For a monopsonist, the marginal expenditure curve lies above the average expenditure curve because the decision to buy an extra unit raises the price that must be paid for all units, including the last unit. All firms should buy inputs so that the marginal value of the last unit is equal to the marginal expenditure on that unit. This is true for both the competitive buyer and the monopsonist. However, because the monopsonist’s marginal expenditure curve lies above the average expenditure curve and because the marginal value curve is downward sloping, the monopsonist buys less than a firm would buy in a competitive market.10. Monopsony power is the power in the factor market held by the buyer. A buyer facing an upward-sloping factor supply curve has some monopsony power. In a competitive market, the seller faces a perfectly-elastic market curve and the buyer faces a perfectly-elastic supply curve. Thus, any characteristic of the market (e.g., when there is a small number of buyers or if buyers engage in collusive behavior) that leads to a less-than-perfectly-elastic supply curve gives the buyer some monopsony power.11. The individual firm’s monopsony power depends on the characteristics of the “buying-side” of the market. There are three characteristics that enhance monopsony power: (1) the elasticity of market supply, (2) the number of buyers, and (3) how the buyers interact. The elasticity of market supply depends on how responsive producers are to changes in price. If, in the short run, supply is relatively fixed, then supply is relatively inelastic. For example, since tobacco farmers can sell their crop to only a handful of tobacco product producers, the power to buy at a price below marginal value is increased.12. With monopsony power, the price is lower and the quantity is less than under competitive buying conditions. Because of the lower price and reduced sales, sellers lose revenue. Only part of this lost revenue is transferred to the buyer as consumer surplus, and the net loss in total surplus is deadweight loss. Even if the consumer surplus could be redistributed to sellers, the deadweight loss persists. This inefficiency will remain because quantity is reduced below a level where price is equal to marginal cost.13. Antitrust laws, which are subject to interpretation by the courts, limit market power by proscribing a firm’s behavior in attempting to maximize profit. Section 1 of the Sherman Act prohibits every restraint of trade, including any attempt to fix prices by buyers or sellers. Section 2 of the Sherman Act prohibits behavior that leads to monopolization. The Clayton Act, with the Robinson-Patman Act, prohibits price discrimination and exclusive dealing (sellers prohibiting buyers from buying goods from other sellers). The Clayton Act also limits mergers when they could substantially lessen competition. The Federal Trade Commission Act makes it illegal to use unfair or deceptive practices.14. Antitrust laws are enforced in three ways: (1) through the Antitrust Division of the Justice Department, whenever firms violate federal statutes, (2) through the Federal Trade Commission, whenever firms violate the Federal Trade Commission Act, and (3) through civil suits. The Justice Department can seek to impose fines or jail terms on managers or owners involved or seek to reorganize the firm, as it did in its case against A.T.& T. The FTC can seek a voluntary understanding to comply with the law or a formal Commission order. Individuals or companies can sue in federal court for awards equal to three times the damage arising from the anti-competitive behavior.1. As illustrated in Figure 10.4b in the textbook, an increase in demand need not always result in a higher price. Under the conditions portrayed in Figure 10.4b, the monopolist supplies different quantities at the same price. Similarly, an increase in supply facing the monopsonist need not always result in a higher price. Suppose theaverage expenditure curve shifts from AE 1 to AE 2, as illustrated in Figure 10.1. With the shift in the average expenditure curve, the marginal expenditure curve shifts from ME 1 to ME 2. The ME 1 curve intersects the marginal value curve (demand curve) at Q 1, resulting in a price of P . When the AE curve shifts, the ME 2 curve intersects the marginal value curve at Q 2 resulting in the same price at P .Figure 10.12. As a large producer of farm equipment, Caterpillar Tractor has market power and should consider the entire demand curve when choosing prices for its products. As their advisor, you should focus on the determination of the elasticity of demand for each product. There are three important factors to be considered. First, how similar are the products offered by Caterpillar’s competitors? If they are close substitutes, a small incr ease in price could induce customers to switch to the competition. Secondly, what is the age of the existing stock of tractors? With an older population of tractors, a 5 percent price increase induces a smaller drop in demand. Finally, because farm tractors are a capital input in agricultural production, what is the expected profitability of the agricultural sector? If farm incomes are expected to fall, an increase in tractor prices induces a greater decline in demand than one would estimate with information on only past sales and prices.3. Yes. The monopolist’s pricing rule as a function of the elasticity of demand for its product is:(P -MC)P = - 1E dor alternatively,d E 1 + 1MC= P ⎪⎪⎪⎭⎫ ⎝⎛⎪⎪⎪⎭⎫ ⎝⎛In this example E d = -2.0, so 1/E d = -1/2; price should then be set so that:2MC = 21MC = P ⎪⎪⎭⎫ ⎝⎛ Therefore, if MC rises by 25 percent price, then price will also rise by 25 percent. When MC = $20, P = $40. When MC rises to $20(1.25) = $25, the price rises to $50, a 25% increase.4. a. The profit-maximizing output is found by setting marginal revenue equal to marginal cost. Given a linear demand curve in inverse form, P = 100 - 0.01Q , we know that the marginal revenue curve will have twice the slope of the demand curve. Thus, the marginal revenue curve for the firm is MR = 100 - 0.02Q . Marginal cost is simply the slope of the total cost curve. The slope of TC = 30,000 + 50Q is 50. So MC equals 50. Setting MR = MC to determine the profit-maximizing quantity:100 - 0.02Q = 50, orQ = 2,500.Substituting the profit-maximizing quantity into the inverse demand function to determine theprice:P = 100 - (0.01)(2,500) = 75 cents.Profit equals total revenue minus total cost:π = (75)(2,500) - (30,000 + (50)(2,500)), orπ = $325 per week.b.Suppose initially that the consumers must pay the tax to the government. Since the total price (including the tax) consumers would be willing to pay remains unchanged, we know that the demand function isP* + T = 100 - 0.01Q, orP* = 100 - 0.01Q - T,where P* is the price received by the suppliers. Because the tax increases the price of each unit, total revenue for the monopolist decreases by TQ, and marginal revenue, the revenue on each additional unit, decreases by T:MR = 100 - 0.02Q - Twhere T = 10 cents. To determine the profit-maximizing level of output with the tax, equate marginal revenue with marginal cost:100 - 0.02Q - 10 = 50, orQ = 2,000 units.Substituting Q into the demand function to determine price:P* = 100 - (0.01)(2,000) - 10 = 70 cents.Profit is total revenue minus total cost:()()()()()000,100000,30000,250000,270=+-=πcents, or$100 per week.Note: The price facing the consumer after the imposition of the tax is 80 cents. The monopolist receives 70 cents. Therefore, the consumer and the monopolist each pay 5 cents of the tax.If the monopolist had to pay the tax instead of the consumer, we would arrive at the same result. The monopolist’s cost function would then beTC = 50Q + 30,000 + TQ = (50 + T)Q + 30,000.The slope of the cost function is (50 + T), so MC = 50 + T. We set this MC to the marginal revenue function from part (a):100 - 0.02Q = 50 +10, orQ = 2,000.Thus, it does not matter who sends the tax payment to the government. The burden of the tax is reflected in the price of the good.5. a.To find the marginal revenue curve, we first derive the inverse demand curve. The intercept of the inverse demand curve on the price axis is 27. The slope of the inverse demand curve is the change in price divided by the change in quantity. For example, a decrease in price from 27 to 24 yields an increase in quantity from 0 to 2.Therefore, the slope is -32and the demand curve isP Q=-2715..The marginal revenue curve corresponding to a linear demand curve is a line with the same intercept as the inverse demand curve and a slope that is twice as steep. Therefore, the marginal revenue curve isMR = 27 - 3Q.b.The monopolist’s maximizing output occurs where marginal revenue equals marginal cost. Marginal cost is a constant $10. Setting MR equal to MC to determine the profit-maximizing quantity:27 - 3Q = 10, or Q=567..To find the profit-maximizing price, substitute this quantity into the demand equation:()().5.18$67.55.127=-=PTotal revenue is price times quantity:()().83.104$67.55.18==TRThe profit of the firm is total revenue minus total cost, and total cost is equal to average cost times the level of output produced. Since marginal cost is constant, average variable cost is equal to marginal cost. Ignoring any fixed costs, total cost is 10Q or 56.67, and profit is10483566717..$48..-=c.For a competitive industry, price would equal marginal cost at equilibrium. Setting the expression for priceequal to a marginal cost of 10:271510-=.Q , or Q =1133..Note the increase in the equilibrium quantity compared to the monopoly solution.d.The social gain arises from the elimination of deadweight loss. Since deadweight loss under monopoly is equal to the difference between the price under monopoly minus the price under competition (18.5 - 10 = 8.5) times the difference between the quantity under competition minus the quantity under monopoly (11.3 - 5.67 = 5.67) times one-half, the deadweight loss is a triangle under the demand curve:(0.5)(8.5)(5.67) = $24.10.Furthermore, consumers gain this deadweight loss plus the monopolist’s profit of $48. The monopolist’s profits are reduced to zero, and the consumer surplus increases by $72.6. a. The average revenue curve is the demand curve,P = 700 - 5Q .For a linear demand curve, the marginal revenue curve has the same intercept as the demand curve and a slope that is twice as steep:MR = 700 - 10Q .Next, determine the marginal cost of producing Q . To find the marginal cost of production in Factory 1, take the first derivative of the cost function with respect to Q :().20111Q dQQ dC = Similarly, the marginal cost in Factory 2 is().40222Q dQQ dC = Rearranging the marginal cost equations in inverse form and horizontally summing them, we obtain total marginal cost, MC T :Q Q Q MC MC MC T =+=+=12122040340, orMC Q T =403. Profit maximization occurs where MC T = MR . See the Figure 10.6.a for the profit-maximizing output for each factory, total output, and price.Figure 10.6.ab.Calculate the total output that maximizes profit, i.e., Q such that MC T = MR :40370010Q Q =-, or Q = 30. Next, observe the relationship between MC and MR for multiplant monopolies:MR = MC T = MC 1 = MC 2.We know that at Q = 30, MR = 700 - (10)(30) = 400.Therefore,MC 1 = 400 = 20Q 1, or Q 1 = 20 andMC 2 = 400 = 40Q 2, or Q 2 = 10.To find the monopoly price, P M , substitute for Q in the demand equation:This means that the demand curve becomes P = 20 - 3Q 2. With an inverse linear demand curve, we know that the marginal revenue curve has the same vertical intercept but twice the slope, or MR = 20 - 6Q 2. To determine the profit-maximizing level of output, equate MR and MC 2:20 - 6Q 2 = 10 + 5Q 2, orQ Q ==2091..Price is determined by substituting the profit-maximizing quantity into the demand equation:()3.1791.0320=-=P .8. a. Although Alcoa controlled about 90 percent of primary aluminum production in the United States, secondary aluminum production by recyclers accounted for 30 percent of the total aluminum supply. Therefore, with a higher price, a much larger proportion of aluminum supply could come from secondary sources. This assertion is true because there is a large stock of potential supply in the economy. Therefore, the price elasticity of demand for Alcoa’s primary aluminum is much higher than we would expect, given Alcoa’s domi nant position in primary aluminum production. In many applications, other metals such as copper and steel are feasible substitutes for aluminum. Again, the demand elasticity Alcoa faces might be lower than we would otherwise expect.b.While Alcoa could not raise its price by very much at any one time, the stock of potential aluminum supply is limited. Therefore, by keeping a stable high price, Alcoa could reap monopoly profits. Also, since Alcoa had originally produced the metal reappearing as recycled scrap, it would have considered the effect of scrap reclamation on future prices. Therefore, it exerted effective monopolistic control over the secondary metal supply.c.Judge Hand ruled against Alcoa but did not order it to divest itself of any of its United States production facilities. The two remedies imposed by the court were (1) that Alcoa was barred from bidding for two primary aluminum plants constructed by the government during World War II (they were sold to Reynolds and Kaiser) and (2) that it divest itself of its Canadian subsidiary, which became Alcan.9. a. Because demand (average revenue) may be described as P = 11 - Q , we know that the marginal revenue function is MR = 11 - 2Q . We also know that if average cost is constant, then marginal cost is constant and equal to average cost: MC = 6.To find the profit-maximizing level of output, set marginal revenue equal to marginal cost:11 - 2Q = 6, or Q = 2.5.That is, the profit-maximizing quantity equals 2,500 units. Substitute the profit-maximizingquantity into the demand equation to determine the price:P = 11 - 2.5 = $8.50.Profits are equal to total revenue minus total cost,π = TR - TC = (AR )(Q ) - (AC )(Q ), orπ = (8.5)(2.5) - (6)(2.5) = 6.25, or $6,250. The degree of monopoly power is given by the Lerner Index:P MC-=-=8560294... b.To determine the effect of the price ceiling on the quantity produced, substitute the ceiling price into the demandequation.7 = 11 - Q , orQ = 4,000.This quantity is the profit-maximizing level of output for the monopolist because, at that level,MR = MC .Profits are equal to total revenue minus total cost:π = (7)(4,000) - (6)(4,000) = $4,000. The degree of monopoly power is:P MC -=-=760143.. c.If the regulatory authority sets a price below $6, the monopolist would prefer to go out of business instead of produce because it cannot cover its average costs. At any price above $6, the monopolist would produce less than the 5,000 units that would be produced in a competitive industry. Therefore, the regulatory agency should set a price ceiling of $6, thus making the monopolist face a horizontal effective demand curve up to Q = 5,000. To ensure a positive output (so that the monopolist is not indifferent between producing 5,000 units and shutting down), the price ceiling should be set at $6 + δ, where δ is small.Thus, 5,000 is the maximum output that the regulatory agency can extract from the monopolistby using a price ceiling. The degree of monopoly power isP MC P -=+-=→66660δδ as δ → 0. 10.a. M MMT should offer enough t-shirts such that MR = MC . In the short run, marginal cost is the change in SRTC as the result of the production of another t-shirt, i.e.,SRMC = 5, the slope of the SRTC curve. Demand is:Q P =100002,, or, in inverse form,P = 100Q-1/2. Total revenue (PQ ) is 100Q 1/2. Taking the derivative of TR with respect to Q , MR = 50Q -1/2. Equating MR and MC to determine the profit-maximizing quantity:5 = 50Q -1/2, or Q = 100.Substituting Q = 100 into the demand function to determine price:P = (100)(100-1/2 ) = 10.The profit at this price and quantity is equal to total revenue minus total cost:π = (10)(100) - (2000 + (5)(100)) = -$1,500.Although profit is negative, price is above the average variable cost of 5 and therefore, the firm should not shut down in the short run. Since most of the firm’s costs are fixed, the firm loses $2,000 if nothing is produced. If the profit-maximizing quantity is produced, the firm loses only $1,500.b.In the long run, marginal cost is equal to the slope of the LRTC curve, which is 6.Equating marginal revenue and long run marginal cost to determine the profit-maximizing quantity:50Q -1/2 = 6 or Q = 69.44Substituting Q = 69.44 into the demand equation to determine price:P = (100)[(50/6)2] -1/2 = (100)(6/50) = 12Therefore, total revenue is $833.33 and total cost is $416.67. Profit is $416.67. The firm should remain in business.c.In the long run, MMMT must replace all fixed factors. Therefore, we can expect LRMC to be higher than SRMC .11. No, production should not shift to the Massachusetts plant, although production in the Connecticut plant should be reduced. In order to maximize profits, a mulitplant firm will schedule production at all plants so that the following two conditions are met:- Marginal costs of production at each plant are equal.- Marginal revenue of the total amount produced is equal to the marginal cost at each plant.These two rules can be summarized as MR = MC1 = MC2= MC3, where the subscript indicates the plant.The firm in this example has two plants and is in a perfectly competitive market. In a perfectly competitive market P = MR. To maximize profits, production among the plants should be allocated such that:(10,000)(n), and marginal expenditure is 10,000. Equating marginal value and marginal expenditure:30,000 - 125n = 10,000, orn = 160.13. a. To maximize profits, DD should equate marginal revenue and marginal cost. Given a demand of P = 55 - 2Q, we know that total revenue, PQ, is 55Q - 2Q2. Marginal revenue is found by taking the first derivative of total revenue with respect to Q or:MRdTRdQQ ==-554.Similarly, marginal cost is determined by taking the first derivative of the total cost function with respect to Q or:MCdTCdQQ==-2 5.Equating MC and MR to determine the profit-maximizing quantity,55 - 4Q = 2Q - 5, orQ = 10.Substituting Q = 10 into the demand equation to determine the profit-maximizing price:P = 55 - (2)(10) = $35.Profits are equal to total revenue minus total cost:π = (35)(10) - (100 - (5)(10) + 102) = $200.Consumer surplus is equal to one-half times the profit-maximizing quantity, 10, times thedifference between the demand intercept (the maximum price anyone is willing to pay) and themonopoly price:CS = (0.5)(10)(55 - 35) = $100.b.In competition, profits are maximized at the point where price equals marginal cost, where price is givenby the demand curve:55 - 2Q = -5 + 2Q, orQ = 15.Consumer surplus isCS = (0.5)(55 - 27)(14) = $196.Profits areπ = (27)(14) - (100 - (5)(14) + 142) = $152.The deadweight loss is $2.00 This is equivalent to a triangle of(0.5)(15 - 14)(27 - 23) = $2e.With a ceiling price set below the competitive price, DD will decrease its output. Equate marginal revenue and marginal cost to determine the profit-maximizing level of output:23 = - 5 + 2Q, or Q = 14.With the government-imposed maximum price of $23, profits areπ = (23)(14) - (100 - (5)(14) + 142) = $96.Consumer surplus is realized on only 14 doorsteps. Therefore, it is equal to the consumersurplus in part d., i.e. $196, plus the savings on each doorstep, i.e.,CS = (27 - 23)(14) = $56.Therefore, consumer surplus is $252. Deadweight loss is the same as before, $2.00.f.With a maximum price of only $12, output decreases even further:12 = -5 + 2Q, or Q = 8.5.Profits areπ = (12)(8.5) - (100 - (5)(8.5) + 8.52) = -$27.75.Consumer surplus is realized on only 8.5 units, which is equivalent to the consumer surplusassociated with a price of $38 (38 = 55 - 2(8.5)), i.e.,(0.5)(55 - 38)(8.5) = $72.25plus the savings on each doorstep, i.e.,(38 - 12)(8.5) = $221.Therefore, consumer surplus is $293.25. Total surplus is $265.50, and deadweight loss is $84.50.11。
平狄克微观经济学答案——第18章 外部性和公共产品
第十八章外部性和公共产品1．在居民住宅占据了城镇的东部之后，几家工厂设立在西部。
每家厂商生产相同的产品，并且在生产中排放有害气体，对社区的居民产生不利的影响。
（1）为什么厂商生产会产生外部性？工厂产生的有害气体会影响居民的效用函数，而且居民不能控制气体的量。
我们可以认为有害气体会减少居民的效用（即负的外部性），降低房地产的价值。
（2）你认为私下讨价还价会解决这一外部性问题吗？请解释。
如果居民预计到工厂的设立，那么房屋价格会反映出有害气体造成的效用低下；通过房屋市场的价格调节使外部性内部化。
如果预计到有害气体，只有当存在数量较少的团体（企业或家庭）且产权界定清晰时，私下的讨价还价才能解决外部性的问题。
私下的讨价还价取决于每个家庭为空气质量支付的意愿，但是真实的信息披露几乎不可能。
工厂已有的生产技术的转化以及工厂和家庭之间的雇佣关系都会使这个问题更加复杂。
私下的讨价还价不大可能解决这个问题。
（3）社区可能会怎样决定空气质量的有效水平?社区可以通过把家庭的支付意愿相加并使其等于减少污染的边际成本来求出空气质量的经济效率水平。
这两步都要求获得真实的信息。
2．一个电脑编程人员游说反对对软件进行版权保护。
他的论点是，每个人都应当从为个人电脑编写的创新程序中获益，，与各种各样电脑程序的接触甚至会鼓舞年轻的编程人员编出更多的创新程序。
考虑到由于它的建议而可能得到的边际社会收益，你同意该编程人员的主张吗？信息中给出的计算机软件是一个经典的公共产品的例子。
因为它可以无成本的复制，所以向一个额外的消费者提供软件的边际成本几乎为零。
所以软件是非竞争性的。
（编写软件的固定成本很高，但可变成本却很低。
）另外，防止消费者复制和使用软件的代价很高，因为只有付出很高的成本或给消费者带来很大不便才能保护版权。
所以，软件也是非排他性的。
由于具有非竞争性和非排他性，计算机软件面临着公共产品：免费搭车者的存在使得市场很难或不可能提供有效率的软件水平。
平狄克微观经济学答案——第17章信息不对称的市场
第17章信息不对称的市场教学注解这一章探求了一部分人比另一部分人知道得更多时的不同情况，或者换言之，当存在不对称信息时会发生什么。
17.1节讨论了卖方比买方拥有更多信息的情况，17.2节讨论了市场信号机制处理不对称信息的问题。
17.3节讨论了当一方对自己的行为比另一方了解得更多时的道德风险。
17.4节讨论了委托——代理问题，17.5节扩展了一体化企业案例的分析。
两节都讲述了所有者与经理的目标不一致的问题。
17.6节检验了效率工资问题。
基本上有四个话题可由指导教师根据时间限制和大多数兴趣从中挑选。
介绍不对称信息最好通过复习微观经济学以完全信息为假定来展开。
例如，除了第5章和15章的几节，我们以对未来完全已知为假设（无不确定性）。
在不确定模型中，消费者和生产者与自然规律博弈。
在不对称信息模型中，他们互相博弈。
你的许多学生可能买卖或将要买卖旧车，因此，他们会觉得柠檬模型有趣。
通过询问旧车的卖者他们如何定价来开始你的讲解。
在展示图17.1前强调对于模型的直觉。
如果他们弄懂了这一模型，他们应当索要更高的价格，以变给买者留下他们的车质量高的印象。
课堂讨论可以考虑政府是否应通过立法，要求出售旧车时提供保证书。
保险市场也是大多数学生所熟悉的市场。
尽管许多州要求汽车保险，责任限制可能每个保险单都不同。
(liability limits may vary from policy to policy.)讨论风险规避者怎样想购买更高赔偿额度的保险单，以及保险公司怎样决定保险的风险。
如果你在15章用了购买房屋的案例，这里你可以通过考虑银行家怎样决定借款者是否违约将其扩展。
当讨论市场信号时，支出教育的双重作用（作为培训和更高生产率的信号）。
在17.2节展示的“工作市场信号的简单模型”，可能会使不熟悉不连续函数的学生困惑不解（见图17.2）。
解释教育程度怎样导致不连续性，强调教育质量的程度、保证和担保的关系。
（stress the relationship between degrees,guarantees,and warranties of educational quality.）道德风险是一个用例子容易解释的概念，但对逆向选择和道德风险的清晰的区别是重要的。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
第四章复习题需求曲线（）一般指表示商品价格和需求数量之间函数关系的、1曲线，是需求表或需求函数的几何表示。
它表明在其它情况不变时消费者在一定时间内在各种可能的价格下愿意而且能够购买的商品数量。
其它情况不变包括：、消费者的收入水平不变；、相关商品的价格不变；、消费者的偏好不变；、消费者对商品的价格预期不变。
个别需求曲线是表明某一个消费者的消费需求数量与商品价格的函数关系的曲线；而市场需求曲线是表明整个消费群体的消费需求数量与商品价格的函数关系的曲线；通过将个别需求曲线进行水平加总可以得出市场需求曲线，两者的主要区别在于它们所表示的需求量的主体不同，一个是某一个消费者，一个是整个消费群体。
在不存在连带外部效应的情况下市场需求曲线具有更大的价格弹性。
对产品某种牌号的需求较对所有牌号的需求更缺乏价格弹性。
因、2为所有牌号的产品面对的是全体消费者；而某种牌号的产品面对的是某些对该牌号具有特殊的偏好的个别群体，显然前者较后者所面对的对象更多，当价格发生相同的变化时前者的变化量自然大，也即其价格弹性大。
额外的一张门票的价值或边际收益是大于10美元的。
因为在价、3格为10美元的情况下需求远大于供给，消费者对门票的支付意愿大于10美元，当在消费一张门票后再消费一张支付意愿在一/般情况下应大于10美元。
测定的方法是实地询问已经买了一张门票的消费者其对再买一张门票的出价最高是多少，这一值就是额外的一张门票的价值或边际收益。
衣服对于他来讲应该是一种正常商品，即随着他的收入的增加其、4对衣服消费量也增加。
因为他仅将收入在衣服和食物间进行分配，即其效用的来源是衣服和食物，当其收入增加时其消费的预算空间扩大，新的效用水平应大于原来的效用水平；而食物消费量随着收入水平的增大而减小，食物相应带来的效用也减小，而总效用增大，则新的衣服消费带来的效用必定增大，则衣服的消费量随着收入的增加也必定增大，所以衣服对于他来讲应该是一种正常商品。
如果一种商品价格的上涨（下跌）导致另一种商品需求量的上升、5（下降），就称这两种商品是替代品；反之则称它们为互补品。
（a）、数学课和经济学课在有些情况下是互补品，在有些情况下是替代品。
如：一个学经济学的学生除学好经济学外必须具备一定的数学知识，当他数学较差时（难以理解现代的经济学的基本数学表达方式），这两门课程是互补品；而如果某一个同学仅仅是为了扩大知识面而学习这两门课程，则它们是替代品；（b）、网球和网球拍是互补品，如果网球价格上升，则将导致打网球的人减少，对网球拍的需求也将减少；（c）、牛排和龙虾是替代品；（d）、目的地相同的飞机旅行和火车旅行是替代品；（d）、熏肉和禽蛋是替代品。
/（a）、（b）为需求曲线的一次移动，当进口外国服装的限额被取、6消时大量的外国服装将使外国服装降价，引起消费者对美国服装的消费偏好减小，使得需求曲线向左下移动；美国公民收入的增加，将有更多的支出用于服装消费，需求曲线将向右上移动。
（c）为沿需求曲线的一次移动，因为只是消费者面临的美国服装的价格下降，其它条件没变。
替代效应是指在实际收入保持不变（消费者的效用数量保持不、7变）的情况下某种商品的价格的变化使得两种商品的交换比率发生变化，引起该商品需求量的变化；收入效应是指某种商品的价格上涨（下降）时，购买同等量的该商品需要更多更少）的收入，即该商品价格的上涨（下降）使得消费者拥有更少（更多）的收入，从而使得该商品的消费量减少（增加）。
（a）价格上涨时盐的收入效应和替代效应都很小，因为盐是一种生活必需品，是不可替代的，价格的变化基本不影响人们的消费量。
（b）住房的替代效应较小，而收入效应较大，住房对消费者的效用与其它商品的替代性较小，而收入的变化对消费者对住房的影响较大，收入效应较大；（c）戏票的收入效应和替代效应都较大，因为戏票是一种奢侈品消费，收入水平的变化对它消费的影响较大，同时它效用又很容易被其它的娱乐活动所取代，所以收入效应和替代效应都较大。
（d）对食物而言收入效应和替代效应都较小，食物是人们维持生活的必需品，其有些特性是其它消费无法替代的，同时人们的食物消费是有一个限度的，过多的食物消费对消费者并 /不一定带来效用，即收入的增加并不一定带来食物消费的大量增长，所以收入效应和替代效应都较小。
该计划使消费者的生活恶化。
因为退税额不可能超过他的纳税、8额，税收政策强行改变他的消费选择，新的消费选择对应的效用小于原来的消费选择对应的效用（汽油税使汽油价格上涨，负的替代效应和负的收入效应使其总效用减小，同时退税使他的收入水平上升，新增的收入不可能超过原来的纳税额度，新增收入带来的效用小于纳税所减少的效用额），生活恶化。
需求的价格弹性是指某商品的价格变化1%时该商品变化的百分、9比。
学生企业经济学家协会的成员资格具有较高的价格弹性，因为学生的收入来源较小，支付能力有限，同时企业经济学家协会的成员资格对他们来说是一种奢侈品，需求曲线较为陡峭；高级经理对企业经济学家协会的成员资格具有较小的价格弹性，因为高级经理的收入较高，支付能力相对较强，同时企业经济学家协会的成员资格对他们来说具有特别重要的意义，需求较为强烈，需求曲线较为平坦。
练习题1、（1），电脑芯片的销售量将下降20%（-2*1020%），软盘驱动器的销售量将下降10%（-1*1010%）。
电脑芯片的销售收入将下降12%（1-110%*（1-20%）=12%）。
软盘驱动器销售收入将下降1%（1-110%*（1-10%）1%）。
（2），根据题中信息可知软盘驱动器给厂商带来的收入已经达到 /，无论降价还是涨价都将使收-1最大化，因为其需求的价格弹性为，降价将使销售量增-2入水平下降；电脑芯片的需求的价格弹性为大并其对收入的影响超过降价对收入的影响，降价将使收入增加。
年1200-55P 令0有P=21.8；2031-209P 令 =0有P=9.7；2、1990211200-55-264P令0有12.24 图中曲线即为小麦总需求曲线20 A 曲线为小麦的国内需求曲线曲线为小麦的国外需求曲线1510D B51000 2000 3000 CE F3、维拉的决定是因为盒式磁带录像机和录像带是互补品，只有有足够的录像带录像机的效用才最大，而制式的录像带制式的录像带较多，同时她朋友拥有的都是制式的录像机，存在一定的攀比效应，所以她选择制式的录像机。
如果引入8毫米录像制式，如果只有制式的录像机支持该制式，则她会选择制式的录像机。
/4、如果不收费则有6单位的人过桥。
（令0，6）过桥费 P A 如果过桥费为6，则消费者剩余损失为12*6/2-（12-6）*3/2=36-9=27126D BO 3 6 C Q过桥人数单位、苹果苹果单)AB收入消费曲线价格消费曲线C) 橙汁(单单位橙汁() 位左鞋(单位)单位左鞋()收入消费曲线价格消费曲线/鞋(右(单位) 单右鞋)位6、由题中信息知对于希瑟而言电影票和租借录像带是完全替代品。
7、（a）、学校安全安全安全计划计划无政府资400000美30000040000035000050000250000350000 30000010000030000020000025000015000015000025000020000020000010000020000010000025000050000150000300000100000（b）、如果300000美元中的50000美元分配给学校选择方案（1）或（2）两者一样，因为两者从政府得到的安全资助相同都为100000美元，用于安全的支出都为350000美元。
如果学校花250000美元则应该选择方案（1），此时从政府得到的安全资助方案（1）大于方案（2），100000>50000；用于安全的最终支出方案（1）大于方案（2）,150000>100000。
学校支出学校支出学校支出300000300000300000200000300000200000 300000 400000 300000400000/安全支出安全支出安全支出、根据题中的信息比尔当前的书和咖啡的消费状态已经达到最优8状态，此时书对于他来说是正常商品，咖啡是劣等品。
无差异曲线预算线咖啡9、（a），由于食物价格为2美元/单位时食物的价格弹性为-1.0，则：纳税使食物价格上涨100%时,对应的弧弹性小于1,即界于-1和0之间。
她的食物消费将下降。
（b），/第四章附录下面的效用函数中哪些符合凸的无差异曲线，哪些不符合？，1u（x，y）=25y（A））=x，yu（（B）0.5（）x和y两过数值的极小。
）（x，y，式中是xu（，y）（C）解：因为a的图形为：y0 x因为的图形为yx。
b所以本题的答案为证明下面的两过效用函数给商品和y带来的是相同的需求函x，2数。
u（x，y）（x）（y）；（a）0.5（）=，Y）xu（）b （解：由a得： /Ｘ＋ＰｙＹ＝Ｉ (1)(x)(y) (2) Ｕ（Ｘ，Ｙ）＝Ｌ）+λ（Ｘ＋ＰｙＹ，λ）（X，Y）Y得：L（X，0λ10λ1Ｘ＋ＰｙＹ＝Ｉ可以得到：2λ22由（b）得：=（）+X L（，Y，λ）0.5）λ（Ｘ＋ＰｙＹ（）+λ0.50.50λ0.5（）+0.50Ｘ＋ＰｙＹ＝Ｉ可以得到：2λ22所以他们的需求函数是一样3．假设有一个效用函数是（X，Y），就如练习1（c）中的那样，那么将因为X价格的变化而引起的X需求的变化进行分解的斯勒茨基 /方程是什么呢？什么是收入效应，什么是替代效应？解：斯勒茨基方程是—X（⊿⊿I），其中第1项是替代效应，第*2项是收入效应。
由于这一类型的效用函数不存在作为价格变化的替代，所以替代效用为零。
第五章一个风险规避者是指收入的边际效用是递减的且在同样的期望1.收入的情况下只愿意选择确定的收入，而一个风险爱好者则更愿意对不确定收入选择不确定的收入且他的收入边际效用是递增的。
在经济学上，风险规避者以及风险爱好者取决于财富的个人效用函数的倾斜程度。
同时，风险规避者或风险爱好者也取决于风险所涉及的性质和个人的收入情况。
取值范围是指在最高的可能收入和最低的可能收入之间的一系2.列的数值。
取值范围并不能描述这些最高收入和最低收入的概率。
方差则考虑了从每一个收入来源于以概率为权数的收入的加权平均，因此在可变性测量中比取值范围更有效。
期望效用值是对不确定事件的所有可能性结果的一个加权平 3.均，而权数正是每种结果发生的概率。
期望效用值的极大化是指个人所做的选择具有具有最高的平均效用，这里的平均效用是在所有可能性的结果中权重最大的。
这个理论要求消费者知道每种结果的可能性，既每个事件发生的概率。
消费者时常既不知道相应事件发生的可能性，也无法评估一些低概率，高回报的事件，在一些情况下，消费者不能有效地评价高回报事件 /的效用水平，比如，对消费者生命的回报。