经济学原理第七章课后题答案
曼昆微观经济学课后练习英文答案(第七章)
✍ how to define and measure consumer surplus.✍ the link between sellers’ costs of producing a good and the supply curve.✍ how to define and measure producer surplus.✍ that the equilibrium of supply and demand maximizes total surplus in a market. CONTEXT AND PURPOSE:Chapter 7 is the first chapter in a three-chapter sequence on welfare economics and market efficiency. Chapter 7 employs the supply and demand model to develop consumer surplus and producer surplus as a measure of welfare and market efficiency. These concepts are then utilized in Chapters 8 and 9 to determine the winners and losers from taxation and restrictions on international trade.The purpose of Chapter 7 is to develop welfare economics—the study of how the allocation of resources affects economic well-being. Chapters 4 through 6 employed supply and demand in a positive framework, which focused on the question, “What is the equilibrium price and quantity in a market?” This chapter now addresses the normative question, “Is the equilibrium price and quantity in a market the best possible solution to the resource allocation problem, or is it simply the price and quantity that balance supply and demand?” Students will discover that under most circumstances the equilibrium price and quantity is also the one that maximizes welfare.KEY POINTS:? Consumer surplus equals buyers’ willingness to pay for a good minus the amount they actually pay for it, and it measures the benefit buyers get from participating in a market.Consumer surplus can be computed by finding the area below the demand curve and above the price.? Producer surplus equals the amount sellers receive for their goods minus their costs of production, and it measures the benefit sellers get from participating in a market. Producer surplus can be computed by finding the area below the price and above the supply curve.? An allocation of resources that maximizes the sum of consumer and producer surplus is said to be efficient. Policymakers are often concerned with the efficiency, as well as the equality, of economic outcomes.? The equilibrium of supply and demand maximizes the sum of consumer and producer surplus.That is, the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently.? Markets do not allocate resources efficiently in the presence of market failures such as market power or externalities.CHAPTER OUTLINE:I. Definition of welfare economics: the study of how the allocation of resources affects economic well-being.A. Willingness to Pay1. Definition of willingness to pay: the maximum amount that a buyer will pay for a good.2. Example: You are auctioning a mint-condition recording of Elvis Presley’s first album. Four buyers show up. Their willingness to pay is as follows:for John. Because John is willing to pay more than he has to for the album,he derives some benefit from participating in the market.3. Definition of consumer surplus: the amount a buyer is willing to pay for a good minus the amount the buyer actually pays for it.4. Note that if you had more than one copy of the album, the price in the auction would end up being lower (a little over $70 in the case of two albums) and both John and Paul would gain consumer surplus.B. Using the Demand Curve to Measure Consumer Surplus1. We can use the information on willingness to pay to derive a demand curve for the rare2. . Because the demand curve shows the buyers’ willingness to pay, we can use the demand curve to measure consumer surplus.C. How a Lower Price Raises Consumer Surplusare paying less for the product than before (area A on the graph).b. Because the price is now lower, some new buyers will enter the market and receive consumer surplus on these additional units of output purchased (area B on the graph).D. What Does Consumer Surplus Measure?1. Remember that consumer surplus is the difference between the amount that buyers are willing to pay for a good and the price that they actually pay.2. Thus, it measures the benefit that consumers receive from the good as the buyers themselves perceive it.III. Producer SurplusA. Cost and the Willingness to Sell1. Definition of cost: the value of everything a seller must give up to produce a good .2. Example: You want to hire someone to paint your house. You accept bids for the work from four sellers. Each painter is willing to work if the price you will pay exceeds her opportunity cost. (Note that this opportunity cost thus represents willingness to sell.) The costs are: ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price ceilings from Chapter 6. Redraw the market for two-bedroom apartments in your town. Draw in a price ceiling below the equilibriumprice.Then go through:✍ consumer surplus before the price ceiling is put into place.✍ consumer surplus after the price ceiling is put into place.You will need to take some time to explain the relationship between the producers’ willingness to sell and the cost of producing the good. The relationship between cost and the supply curve is not as apparent as the relationship between the demand curve and willingness to pay. It is important to stress that consumer surplus is measured in monetary terms. Consumer surplus gives us a way to place a monetary cost on inefficient market outcomes (due to government involvement or market failure).except for Grandma. Because Grandma receives more than she would require to paint the house, she derives some benefit from producing in the market.4.Definition of producer surplus: the amount a seller is paid for a good minus the seller’s cost of providing it.5. Note that if you had more than one house to paint, the price in the auction would end up being higher (a little under $800 in the case of two houses) and both Grandma and Georgia would gain producer surplus.B. Using the Supply Curve to Measure Producer Surplus1. We can use the information on cost (willingness to sell) to derive a supply curve for2. marginal seller . Because the supply curve shows the sellers’ cost (willingness to sell), we can use the supply curve to measure producer surplus.are receiving more for the product than before (area C on the graph).b. Because the price is now higher, some new sellers will enter the market and receive producer surplus on these additional units of output sold (area D on the graph).D. Producer surplus is used to measure the economic well-being of producers, much like consumer surplus is used to measure the economic well-being of consumers.ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price floors from Chapter 6. Redraw the market for anagricultural product such as corn. Draw in a price support above the equilibriumprice.Then go through:✍ producer surplus before the price support is put in place.✍ producer surplus after the price support is put in place.Make sure that you discuss the cost of the price support to taxpayers.IV.Market EfficiencyA. The Benevolent Social Planner1. The economic well-being of everyone in society can be measured by total surplus, which is the sum of consumer surplus and producer surplus:Total Surplus = Consumer Surplus + Producer SurplusTotal Surplus = (Value to Buyers – Amount Paid by Buyers) +(Amount Received by Sellers – Cost to Sellers)Because the Amount Paid by Buyers = Amount Received bySellers:2. Definition of efficiency: the property of a resource allocation of maximizing the total surplus received by all members of society .3. Definition of equality: the property of distributing economic prosperity uniformly the members of society .a. Buyers who value the product more than the equilibrium price will purchase the product; those who do not, will not purchase the product. In other words, the free market allocates the supply of a good to the buyers who value it most highly, as measured by their willingness to pay.b. Sellers whose costs are lower than the equilibrium price will produce the product; those whose costs are higher, will not produce the product. In other words, the free market allocates the demand for goods to the sellers who can produce it at the lowest cost.to the marginal buyer is greater than the cost to the marginal seller so total surplus would rise if output increases.b. At any quantity of output greater than the equilibrium quantity, the value of the product to the marginal buyer is less than the cost to the marginal seller so total surplus would rise if output decreases.3. Note that this is one of the reasons that economists believe Principle #6: Markets are usually a good way to organize economic activity.It would be a good idea to remind students that there are circumstances whenthe market process does not lead to the most efficient outcome. Examplesinclude situations such as when a firm (or buyer) has market power over priceor when there are externalities present. These situations will be discussed inlater chapters.Pretty Woman, Chapter 6. Vivien (Julia Roberts) and Edward (Richard Gere)negotiate a price. Afterward, Vivien reveals she would have accepted a lowerprice, while Edward admits he would have paid more. If you have done a goodjob of introducing consumer and producer surplus, you will see the light bulbsgo off above your students’ heads as they watch this clip.C. In the News: Ticket Scalping1. Ticket scalping is an example of how markets work to achieve an efficient outcome.2. This article from The Boston Globe describes economist Chip Case’s experience with ticket scalping.D. Case Study: Should There Be a Market in Organs?1. As a matter of public policy, people are not allowed to sell their organs.a. In essence, this means that there is a price ceiling on organs of $0.b. This has led to a shortage of organs.2. The creation of a market for organs would lead to a more efficient allocation of resources, but critics worry about the equity of a market system for organs.V. Market Efficiency and Market FailureA. To conclude that markets are efficient, we made several assumptions about how markets worked.1. Perfectly competitive markets.2. No externalities.B. When these assumptions do not hold, the market equilibrium may not be efficient.C. When markets fail, public policy can potentially remedy the situation. SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1 and the consumer surplus that results from that price is denoted CS. Consumer surplus is the amount a buyer is willing to pay for a good minus the amount the buyer actually pays for it. It measures the benefit to buyers of participating in a market.Figure 1 Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1 and the producer surplus that results from that price is denoted PS. Producer surplus is the amount sellers are paid for a good minus the sellers’ cost of providing it (measured by the supply curve). It measures the benefit to sellers of participating in a market.Figure 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1, consumer surplus is CS, and producer surplus is PS. Producing more turkeys than the equilibrium quantity would lower total surplus because the value to the marginal buyer would be lower than the cost to the marginal seller on those additional units.Questions for Review1. The price a buyer is willing to pay, consumer surplus, and the demand curve are all closely related. The height of the demand curve represents the willingness to pay of the buyers. Consumer surplus is the area below the demand curve and above the price, which equals the price that each buyer is willing to pay minus the price actually paid.2. Sellers' costs, producer surplus, and the supply curve are all closely related. The height of the supply curve represents the costs of the sellers. Producer surplus is the area below the price and above the supply curve, which equals the price received minus each seller's costs of producing the good.Figure 43. Figure 4 shows producer and consumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum of consumer surplus and producer surplus. But efficiency may not be the only goal of economic policymakers; they may also be concerned about equity the fairness of the distribution of well-being.5. The invisible hand of the marketplace guides the self-interest of buyers and sellers into promoting general economic well-being. Despite decentralized decision making and self-interested decision makers, free markets often lead to an efficient outcome.6. Two types of market failure are market power and externalities. Market power may cause market outcomes to be inefficient because firms may cause price and quantity to differ from the levels they would be under perfect competition, which keeps total surplus from being maximized. Externalities are side effects that are not taken into account by buyers and sellers. As a result, the free market does not maximize total surplus.Problems and Applications1. a. Consumer surplus is equal to willingness to pay minus the price paid. Therefore, Melissa’s willingness to pay must be $200 ($120 + $80).b. Her consumer surplus at a price of $90 would be $200 ? $90 = $110.c. If the price of an iPod was $250, Melissa would not have purchased one because the price is greater than her willingness to pay. Therefore, she would receive no consumer surplus.2. If an early freeze in California sours the lemon crop, the supply curve for lemons shifts to the left, as shown in Figure 5. The result is a rise in the price of lemons and a decline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 5 Figure 6In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, as shown in Figure 6. The result is a rise in the price of lemonade and a decline in consumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumer surplus in one market often has effects on consumer surplus in other markets.3. A rise in the demand for French bread leads to an increase in producer surplus in the market for French bread, as shown in Figure 7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 8. As a result, the price of flour rises, increasing producer surplus from area Dto D + E + F. Note that an event that affects producer surplus in one market leads to effects on producer surplus in related markets.Figure 84. a.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. His consumer surplus is shown as area A in the figure. He values his first bottle of water at $7, but pays only $4 for it, so has consumer surplus of $3. He values his second bottle of water at $5, but pays only $4for it, so has consumer surplus of $1. Thus Bert’s total consumer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottles of water, an increase of one. His consumer surplus consists of both areas A and B in the figure, an increase in the amount of area B. He gets consumer surplus of $5 from the first bottle ($7 value minus $2 price), $3 from the second bottle ($5 value minus $2 price), and $1 from the third bottle ($3 value minus $2 price), for a total consumer surplus of $9. Thus consumer surplus rises by $5 (which is the size of area B) when the price of a bottle of water falls from $4 to $2.5. a.Figure 10b. When the price of a bottle of water is $4, Ernie sells two bottles of water. His producer surplus is shown as area A in the figure. He receives $4 for his first bottle of water, but it costs only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs $3 to produce, so he has producer surplus of $1. Thus Ernie’s total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottles of water, an increase of one. His producer surplus consists of both areas A and B in the figure, an increase by the amount of area B. He gets producer surplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thus producer surplus rises by $5 (which is the size of area B) when the price of a bottle of water rises from $4 to $6.6. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantityequilibrium quantity of two.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shown in Problems 3 and 4 above. Total surplus is $4 + $4 = $8.c. If Ernie produced one less bottle, his producer surplus would decline to $3, as shown in Problem 4 above. If Bert consumed one less bottle, his consumer surplus would decline to $3, as shown in Problem 3 above. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but the price is only $4, so his producer surplus would decline by $1. If Bert consumed one additional bottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.7. a. The effect of falling production costs in the market for stereos results in a shift to the right in the supply curve, as shown in Figure 11. As a result, the equilibrium price of stereos declines and the equilibrium quantity increases.Figure 11b. The decline in the price of stereos increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D. Prior to the shift in supply, producer surplus was areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amount F + G – B, which may be positive or negative. The increase in quantity increases producer surplus, while the decline in the price reduces producer surplus. Because consumer surplus rises by B + C + D and producer surplus rises by F + G – B, total surplus rises by C + D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curve benefits consumers most. To take the most dramatic case, suppose the supply curve were horizontal, as shown in Figure 12. Then there is no producer surplus at all. Consumers capture all the benefits of falling production costs, with consumer surplus rising from area A to area A + B.Figure 128. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at a quantity of three haircuts and a price between $4 and $5. Firms A, C, and D should cut the hair of Ellen, Jerry, and Phil. Oprah’s willingness to pay is too low and firm B’s costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which totals $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 value minus $4 cost for the third).Figure 139. a. The effect of falling production costs in the market for computers results in a shift to the right in the supply curve, as shown in Figure 14. As a result, the equilibrium price of computers declines and the equilibrium quantity increases. The decline in the price of computers increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D.Figure 14 Figure 15Prior to the shift in supply, producer surplus was areas B + E (the area above thesupply curve and below the price). After the shift in supply, producer surplus isareas E + F + G. So producer surplus changes by the amount F + G – B, whichmay be positive or negative. The increase in quantity increases producer surplus,while the decline in the price reduces producer surplus. Because consumer surplusrises by B + C + D and producer surplus rises by F + G – B, total surplus rises byC +D + F + G.b. Because typewriters are substitutes for computers, the decline in the price of computers means that people substitute computers for typewriters, shifting the demand for typewriters to the left, as shown in Figure 15. The result is a decline in both the equilibrium price and equilibrium quantity of typewriters. Consumer surplus in the typewriter market changes from area A + B to A + C, a net change of C – B. Producer surplus changes from area C + D + E to area E, a net loss of C + D. Typewriter producers are sad about technological advances in computers because their producer surplus declines.c. Because software and computers are complements, the decline in the price and increase in the quantity of computers means that the demand for software increases, shifting the demand for software to the right, as shown in Figure 16. The result is an increase in both the price and quantity of software. Consumer surplus in the software market changes from B + C to A + B, anet change of A – C. Producer surplus changes from E to C + D + E, an increase of C + D, so software producers should be happy about the technological progress in computers.Figure 16d. Yes, this analysis helps explain why Bill Gates is one the world’s richest people, because his company produces a lot of software that is a complement with computers and there has been tremendous technological advance in computers.10. a. With Provider A, the cost of an extra minute is $0. With Provider B, the cost of anextra minute is $1.b. With Provider A, my friend will purchase 150 minutes [= 150 – (50)(0)]. WithProvider B, my friend would purchase 100 minutes [= 150 – (50)(1)].c. With Provider A, he would pay $120. The cost would be $100 with Provider B.Figure 17d. Figure 17 shows the friend’s demand. With Provider A, he buys 150 minutes andhis consumer surplus is equal to (1/2)(3)(150) – 120 = 105. With Provider B, hisconsumer surplus is equal to (1/2)(2)(100) = 100.e. I would recommend Provider A because he receives greater consumer surplus.11. a. Figure 18 illustrates the demand for medical care. If each procedure has a price of $100, quantity demanded will be Q1 procedures.Figure 18b. If consumers pay only $20 per procedure, the quantity demanded will be Q2 procedures. Because the cost to society is $100, the number of procedures performed is too large to maximize total surplus. The quantity that maximizes total surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers get procedures whose value is less than the cost of producing them. As a result, the economy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost of the procedure. But this would require eliminating insurance. Another possibility would be that the insurance company, which pays most of the marginal cost of the procedure ($80, in this case) could decide whether the procedure should be performed. But the insurance company does not get the benefits of the procedure, so its decisions may not reflect the value to the consumer.。
经济学原理习题七
1.以下哪一种是正外部性的例子?A.Dev 为Hillary 修剪草坪,并因这项工作得到100 美元的报酬。
B.在修剪草坪时,Dev的修剪草机喷出烟雾,而Hillary 的邻居Kristen不得不吸入。
C.Hillary的新修剪的草坪使她所在的社区更有吸引力。
D.如果Hillary答应定期修剪草坪,她的邻居会向她付费。
正确答案:C2.如一种物品的生产引起了负外部性,那么,社会成本曲线就在供给曲线( )而且社会均衡数量( )的最优数量A.上方,大于B.上方,小千C.下方,大于D.下方,小于正确答案:B3.当政府对一种物品征收的税等于与生产这种物品相关的外部成本时,它就( )消费者支付的价格,并使市场结果()效率。
A.提高了,更有B.提高了,更无C.降低了,更有D.降低了,更无正确答案:A4.在以下哪一种情况下,科斯定理并不适用?()A.双方之间存在严重的外部性。
B.法院系统可以有效地执行所有合约。
C.双方都完全了解外部性。
D.交易成本使谈判变得困难。
正确答案:D5.以下哪一类物品具有排他性?A.私人物品与俱乐部物品。
B.私人物品与公共资源。
C.公共物品与俱乐部物品。
D.公共物品与公共资源。
正确答案:A6.以下哪一类物品具有消费中的竞争性?()A.私人物品与俱乐部物品。
B.私人物品与公共资源C.公共物品与俱乐部物品。
D.公共物品与公共资源。
正确答案:B7.以下哪一种是公共物品的例子?A.住房。
B.国防。
C.餐馆的饮食。
D.海洋中的鱼。
正确答案:B8.公共资源( )A.可以由市场力量有效率地提供B.如果没有政府就会提供不足C.如果没有政府就会使用过多D.是一种自然垄断正确答案:C7.教育是()A.私人物品B.公共物品C.共有资源D.俱乐部物品正确答案:A1.与公共物品相关的外部性通常是正的。
()A.正确B.错误正确答案:A2.自由市场上的公共物品数量通常大于效率的数量。
()A.正确B.错误正确答案:B12. 与公共资源相关的外部性通常是正的。
宏观经济学第七章习题及答案
第七单元经济周期理论本单元所涉及到的主要知识点：1．经济周期的含义、阶段与种类； 2．经济周期的原因；3．卡尔多经济周期模型； 4．乘数－加速数模型一、单项选择1．经济周期中的两个主要阶段是（）。
a．繁荣和萧条； b．繁荣和衰退； c．萧条和复苏； d．繁荣和复苏。
2．下列对经济周期阶段排序正确的是（）。
a．复苏，繁荣，衰退，萧条； b．复苏，繁荣，萧条，衰退；c．复苏，萧条，衰退，繁荣； d．复苏，衰退，萧条，繁荣。
3．由于经济衰退而形成的失业属于：（）。
a．摩擦性失业； b．结构性失业；c．周期性失业； d．自然失业。
4．下列哪种说法表达了加速原理（）。
a．消费支出随着投资支出增长率的变化而变化；b．投资支出随着国民收入增量的变化而变化；c．国民收入随着投资支出的变化而变化；d．投资支出的减少会造成消费支出一轮一轮地减少。
5．下列哪种说法没有表达加速原理（）。
a．国民收入增长率的变化将导致投资支出的变化；b．消费支出的变化会引起投资支出更大的变化；c．投资支出的减少会造成消费支出一轮一轮地减少；d．投资支出随着国民收入增量的变化而变化。
6．加速原理发生作用的条件是（）。
a．投资的增加会导致国民收入增加；b．消费品的生产需要有一定数量的资本品，因而消费支出的增加会导致投资支出的增加；c．投资的增加会导致消费支出的持续增加；d．投资支出的减少会造成消费支出地减少。
7．经验统计资料表明，在经济周期里，波动最大的一般是（）。
a．资本品的生产； b．农产品的生产； c．日用消费品的生产； d．a和c。
8．所谓资本形成是指（）。
a．净投资； b．总投资； c．更新投资； d．存货的投资。
9．假定某经济连续两年的国民收入都是1200亿美元，在资本－产量比率等于2的条件下，净投资等于（）。
a．1200亿美元； b．2400亿美元； c．2000亿美元； d．0。
10．已知某经济某一年的国民收入是1000亿美元，净投资为零；第二年国民收入增至1200亿美元。
微观经济学第第七章课后答案资料
微观经济学第第七章课后答案第7章 课后练习答案一、基本概念 1、一般均衡：经济中所有经济单位及其市场同时处于均衡的一种状态。
2、帕累托最优条件：1）交换的帕累托最化条件：A B XY XY MRS MRS = ；2）生产的帕累托最优条件：C D LK LK MRTS MRTS = ；3）交换和生产的帕累托最优条件：XY XY MRS MRT = 3、帕累托改进：在资源既定的情况下，如果经济社会通过资源重新配置可以在不使得他人境况受到损害的条件下使得某些人的境况得到改善，则社会福利得到增进。
二、分析简答1、什么是局部均衡和一般均衡，两者的区别和联系是什么？答：局部均衡是指：仅仅是某一种产品实现了均衡或某一种市场(例如，产品市场或要素市场)实现了均衡。
一般均衡是指经济中所有经济单位及其市场同时处于均衡的一种状态。
局部均衡把市场上其他商品和生产要素的数量与价格对这种商品或生产要素价格的影响忽略不计或视为不变，即假定这一商品或生产要素的价格只取决于它本身的供求状况，而不受其他商品的价格和供求状况的影响。
而在一般均衡分析中，不仅要分析影响该商品价格变动的供求关系，还要分析影响该商品生产的生产要素市场、消费者收入等多种因素的影响，即把经济中的所有经济单位和所有市场联系起来加以考虑和分析。
2、为什么完全竞争可以实现帕累托最优所需具备的三个条件？完全竞争经济在一定的假设条件下存在着一般均衡，即存在一组价格，在该组价格下市场中的供求平衡。
假设该组价格为Px ，P Y ，…，P L ，P K ，…。
其中P X ，P Y ，…表示商品X ，Y ，…的均衡价格；P L ，P K ，…表示要素L ，K ，…的均衡价格。
在完全竞争条件下，每个消费者和生产者都是价格的接受者，消费者在既定价格下追求自身效用的最大化，生产者在既定价格下追求自身利润的最大化。
对于消费者而言，任意一个消费者在完全竞争经济中效用最大化的条件是任意两种商品的边际替代率等于两种商品的价格比率，对于消费者C ，有：/A XY X Y MRS P P = ；对于消费者B ，有： /B XY X Y MRS P P =；将以上两式整理可得：A B XY XY MRS MRS =；此公式就是交换的帕累托最优条件。
曼昆《经济学原理》第6版 微观经济学分册 第7章 课后习题答案p157p159
第三篇市场和福利第七章消费者、生产者与市场效率问题与应用1．Melissa用120美元购买了一个iPod，并得到了80美元的消费者剩余。
A．她的支付意愿是多少？答：消费者剩余等于支付意愿减去付出的价格。
因此，梅莉莎须支付200 美元($120 + $80)。
B．如果她在降价销售时买了售价为90美元的iPod，她的消费者剩余会是多少？答：此时，她的消费者剩余为：200-90 =110 美元。
C．如果iPod的价格是250美元，她的消费者剩余会是多少？答：如果iPod 的价格是250 美元，其价格大于梅莉莎的支付愿意，因此她不会再买，这时的消费者剩余就为零。
2．加利福尼亚早来的寒流使柠檬变酸。
柠檬市场上消费者剩余会有什么变动？柠檬水市场上消费者剩余会有什么变动？用图形说明你的答案。
答：柠檬变酸，消费者对柠檬的评价下降，需求曲线向左下方移动。
在其他条件不变的情况下，消费者剩余减少。
如图7－2(a)所示，柠檬质量下降，使需求曲线从D1下降到D 2，△APE是原先的消费者剩余，△A′P′E′是变动后的消费者剩余，△APE>△A′P′E′。
由于柠檬价格的下降，柠檬水的投入成本减少，柠檬水的价格也下降。
在其他条件不变的情况下，柠檬水市场上消费者剩余增加，如图7－2(b)所示。
图7－2 寒流的影响3．假设对法国面包的需求增加。
在法国面包市场上，生产者剩余会发生什么变动？在面粉市场上，生产者剩余会发生什么变动？用图形说明你的答案。
答：由于需求增加，在其他条件不变的情况下，法国面包的价格会上升，市场上的生产者剩余增加。
如图7 －3(a)，价格从P1 上升到P2 ，销量从Q 1上升到Q 2，生产者剩余从面积P1BE1增加到面积P2BE2 。
由于面包产量上升，它的生产要素面粉的需求量也会上升。
在其他条件不变的情况下，面粉价格上升，市场上的生产者剩余增加。
如图7－3(b)所示，生产者剩余从面积P1BE1增加到面积P2BE2 。
经济学原理第七章课后题答案
第七章 消费者、生产者与市场效率复习题：1、解释买者的支付意愿、消费者剩余和需求曲线如何相关。
答：需求曲线反映了买者的支付意愿。
在任何一种数量时，需求曲线给出的价格表示边际买者的支付意愿。
需求曲线以下和价格以上的总面积是一种物品或劳务市场上所有买者消费者剩余的总和。
2、解释卖者的成本、生产者剩余和供给曲线如何相关。
答：供给曲线的高度与卖者的成本相关。
在任何一种数量时，供给曲线给出的价格表示边际卖者的成本。
供给曲线以上和价格以下的总面积衡量市场的生产者剩余。
3、在供求图中，说明市场均衡时的生产者和消费者剩余。
答：4、什么是效率？它是经济决策者的唯一目标吗？答：效率是指资源配置使社会所有成员得到的总剩余最大化的性质。
价格均衡价格数量 APE 的面积代表消费者剩余；PBE 的面积代表生产者剩余。
除了效率外，经济决策者还应该关心平等。
实际上，市场交易的好处很像在市场参与者之间分割一块蛋糕，经济决策者不仅要关心如何奖经济蛋糕做大，即效率；还要考虑如何在市场参与者之间分割这块蛋糕，这就涉及公平问题。
5、看不见的手有什么作用？答：每一个市场参与者都会尽力追求自己的利益，看不见的手指引他们在相互竞争中达到一个并非他们本意想要达到的目的，这就是市场均衡点。
在均衡点上，消费者剩余和生产者剩余总和最大化，整个社会福利达到最大。
6、说出两种市场失灵的名字。
解释为什么每一种都可能使市场结果无效率。
答：市场失灵包括市场势力和外部性。
如果某一市场上存在市场势力，即只有极少部分（可能是一个）买者或卖者可以控制的市场价格，他们就会使价格倾向于对他们这一小部分人有益的水平。
于是，市场价格和数量背离供求平衡，社会福利达不到最大，市场失去效率。
外部性是某些市场参与者的行为对旁观者福利的影响。
它使市场福利还要取决于买者评价和卖者成本之外的其他因素。
由于买者和卖者在决定消费和生产时并没有考虑这种负作用。
所有，从整个社会角度来看，市场均衡可能是无效率的。
经济学原理曼昆课后答案chapter7.doc
Problems and Applications1.If an early freeze in California sours the lemon crop, the supply curve for lemons shiftsto the left, as shown in Figure 7-5.The result is a rise in the price of lemons and adecline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 7-5In the market for lemonade, the higher cost of lemons reduces the supply of lemonade,as shown in Figure 7-6.The result is a rise in the price of lemonade and a decline inconsumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affectsconsumer surplus in one market often has effects on consumer surplus in other markets.Figure 7-62. A rise in the demand for French bread leads to an increase in producer surplus in themarket for French bread, as shown in Figure 7-7.The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7-7The increased quantity of French bread being sold increases the demand for flour, asshown in Figure 7-8.As a result, the price of flour rises, increasing producer surplusfrom area D to D + E + F. Note that an event that affects producer surplus in onemarket leads to effects on producer surplus in related markets.Figure 7-83. a.Bert’ s demand schedule is:Price Quantity DemandedMore than $7 0$5 to $7 1$3 to $5 2$1 to $3 3$1 or less 4Bert’ s demand curve is shown in Figure 7 -9.Figure 7-9b.When the price of a bottle of water is $4, Bert buys two bottles of water.Hisconsumer surplus is shown as area A in the figure.He values his first bottle ofwater at $7, but pays only $4 for it, so has consumer surplus of $3.He valueshis second bottle of water at $5, but pays only $4 for it, so has consumersurplus of $1.Thus Bert’ s total consumer surplus is $3 + $1 = $4, which isthe area of A in the figure.c.When the price of a bottle of water falls from $4 to $2, Bert buys three bottlesof water, an increase of one. His consumer surplus consists of both areas Aand B in the figure, an increase in the amount of area B. He gets consumersurplus of $5 from the first bottle ($7 value minus $2 price), $3 from thesecond bottle ($5 value minus $2 price), and $1 from the third bottle ($3 valueminus $2 price), for a total consumer surplus of $9. Thus consumer surplusrises by $5 (which is the size of area B) when the price of a bottle of water fallsfrom $4 to $2.4. a. Ernie ’ s supply schedule for water is:Price Quantity SuppliedMore than $7 4$5 to $7 3$3 to $5 2$1 to $3 1Less than $1 0Ernie’ s supply curve is shown in Figure 7 -10.Figure 7-10b.When the price of a bottle of water is $4, Ernie sells two bottles of water.Hisproducer surplus is shown as area A in the figure.He receives $4 for his firstbottle of water, but it costs only $1 to produce, so Ernie has producer surplusof $3.He also receives $4 for his second bottle of water, which costs $3 toproduce, so he has producer surplus of$1. Thus Ernie’ s total producersurplus is $3 + $1 = $4, which is the area of A in the figure.c.When the price of a bottle of water rises from $4 to $6, Ernie sells three bottlesof water, an increase of one.His producer surplus consists of both areas Aand B in the figure, an increase by the amount of area B.He gets producersurplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the secondbottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5price), for a total producer surplus of $9.Thus producer surplus rises by $5(which is the size of area B) when the price of a bottle of water rises from $4to $6.5. a. From Ernie ’ s supply schedule and Bert ’ s demand schedule, the quantitydemanded and supplied are:Price Quantity Supplied Quantity Demanded$ 2 1 34 2 26 3 1Only a price of $4 brings supply and demand into equilibrium, withan equilibrium quantity of 2.b.At a price of $4, consumer surplus is $4 and producer surplus is $4, as shownin problems 3 and 4.Total surplus is $4 + $4 = $8.c.If Ernie produced one fewer bottle, his producer surplus would decline to $3,as shown in problem 4.If Bert consumed one fewer bottle, his consumersurplus would decline to $3, as shown in problem 3. So total surplus would declineto $3 + $3 = $6.d.If Ernie produced one additional bottle of water, his cost would be $5, but theprice is only $4, so his producer surplus would decline by $1.If Bertconsumed one additional bottle of water, his value would be $3, but the priceis $4, so his consumer surplus would decline by $1.So total surplus declinesby $1 + $1 = $2.6. a.The effect of falling production costs in the market for stereos results in a shiftto the right in the supply curve, as shown in Figure 7-11.As a result, theequilibrium price of stereos declines and the equilibrium quantity increases.b.The decline in the price of stereos increases consumer surplus from area A to A+ B + C + D, an increase in the amount B + C + D.Prior to the shift in supply,producer surplus was areas B + E (the area above the supply curve and belowthe price).After the shift in supply, producer surplus is areas E + F + G.Soproducer surplus changes by the amount F + G - B, which may be positive ornegative.The increase in quantity increases producer surplus, while thedecline in the price reduces producer surplus.Since consumer surplus risesby B + C + D and producer surplus rises by F + G - B, total surplus rises by C+ D+F+G.c.If the supply of stereos is very elastic, then the shift of the supply curvebenefits consumers most.To take the most dramatic case, suppose thesupply curve were horizontal, as shown in Figure 7-12.Then there is noproducer surplus at all.Consumers capture all the benefits of fallingproduction costs, with consumer surplus rising from area A to area A + B.Figure 7-11Figure 7-127. Figure 7-13 shows supply and demand curves for haircuts. Supply equals demand ata quantity of three haircuts and a price between $4 and $5. Firms A, C, and D shouldcut the hair of Sally Jessy, Jerry, and Montel. Oprah ’ s willingness to pay is too low and firm B ’ s costs are too high, so they do not participate. The maximum total surplus isthe area between the demand and supply curves, which totals $11 ($8 value minus$2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 valueminus $4 cost for the third).Figure 7-138. a.The effect of falling production costs in the market for computers results in ashift to the right in the supply curve, as shown in Figure 7-14.As a result, theequilibrium price of computers declines and the equilibrium quantity increases.The decline in the price of computers increases consumer surplus from area Ato A + B + C + D, an increase in the amount B + C + D.Figure 7-14Prior to the shift in supply, producer surplus was areas B + E (the area abovethe supply curve and below the price).After the shift in supply, producersurplus is areas E + F + G.So producer surplus changes by the amount F + G- B, which may be positive or negative.The increase in quantity increasesproducer surplus, while the decline in the price reduces producer surplus. Sinceconsumer surplus rises by B + C + D and producer surplus rises by F + G - B,total surplus rises by C + D + F + G.——Figure 7-15b.Since adding machines are substitutes for computers, the decline in the priceof computers means that people substitute computers for adding machines,shifting the demand for adding machines to the left, as shown in Figure 7-15.The result is a decline in both the equilibrium price and equilibrium quantity ofadding machines.Consumer surplus in the adding-machine market changesfrom area A + B to A + C, a net gain of C - B.Producer surplus changes fromarea C + D + E to area E, a net loss of C + D.Adding machine producers aresad about technological advance in computers because their producersurplus declines.c.Since software and computers are complements, the decline in the price andincrease in the quantity of computers means that people’ s demand forsoftware increases, shifting the demand for software to the right, as shown inFigure 7-16. The result is an increase in both the price and quantity of software.Consumer surplus in the software market changes from B + C to A+B, a net increase of A - C. Producer surplus changes from E to C + D + E, anincrease of C + D, so software producers should be happy about the technologicalprogress in computers.d.Yes, this analysis helps explain why Bill Gates is one the world’ s richest msince his company produces a lot of software that’ s a complement withcomputers and there has been tremendous technological advance incomputers.——Figure 7-169. a. Figure 7-17 illustrates the demand for medical care. If each procedure has aprice of $100, quantity demanded will be Q 1 procedures.Figure 7-17b.If consumers pay only $20 per procedure, the quantity demanded will be Q 2procedures.Since the cost to society is $100, the number of proceduresperformed is too large to maximize total surplus.The quantity thatmaximizes total surplus is Q 1 procedures, which is less than Q2.c.The use of medical care is excessive in the sense that consumers getprocedures whose value is less than the cost of producing them.As a result,——the economy’ s total surplus is reduced.d.To prevent this excessive use, the consumer must bear the marginal cost ofthe procedure.But this would require eliminating insurance.Anotherpossibility would be that the insurance company, which pays most of themarginal cost of the procedure ($80, in this case) could decide whether theprocedure should be performed.But the insurance company doesn’ t get thebenefits of the procedure, so its decisions may not reflect the value to theconsumer.10. a. Figure 7-18 illustrates the effect of the drought. The supply curve shifts tothe left, leading to a rise in the equilibrium price from P 1 to P 2 and a decline inthe equilibrium quantity from Q 1 to Q 2 .Figure 7-18b.If the price of water is not allowed to change, there will be an excess demandfor water, with the shortage shown on the figure as the difference between Q 1and Q 3 .c.The system for allocating water is inefficient because it no longer allocateswater to those who value it most highly.Some people who value water atmore than its cost of production will be unable to obtain it, so societysurplus isn’ t maximized.The allocation system seems unfair as well.Water is allocated simply on pastusage, rewarding past wastefulness.If a family’ s demand for water increases,——say because of an increase in family size, the policy doesn ’ t allow them to obtain more water. Poor families, who probably used water mostly fornecessary uses like drinking, would suffer more than wealthier families whowould have to cut back only on luxury uses of water like operating backyardfountains and pools. However, the policy also keeps the price of water lower,which benefits poor families, since otherwise more of their family budgetwould have to go for water.d. If the city allowed the price of water to rise to its equilibrium price P 2 , theallocation would be more efficient. Quantity supplied would equal quantitydemanded and there would be no shortage. Total surplus would bemaximized.Whether the market allocation would be more or less fair than theproportionate reduction in water under the old policy is difficult to say, but it islikely to be more fair. Notice that the quantity supplied would be higher (Q 2)in this case than under the water restrictions (Q 3 ), so there ’ s less reduction inwater usage. To make the market solution even more fair, the governmentcould provide increased tax relief or welfare payments for poor families whosuffer from paying the higher water prices.。
高鸿业课后答案第七章
第七章一、填空题1、完全垄断市场上短期均衡的条件是，长期均衡的条件是。
MR=MC，MR=LMC=SMC2、在完全竞争市场上，厂商短期均衡的条件是，长期均衡的条件是。
SMR=SMC，MR=MC=AR=AC3、引起垄断竞争的基本条件是，另一个条件是。
产品差别，存在较多的厂商4、在完全竟争市场上，平均收益边际收益；而在其他市场上，一般是平均收益边际收益。
等于，大于5、在完全竞争市场上，一家厂商所面临的需求曲线是，而在完全垄断市场上，一家厂商所面临的需求曲线是。
水平线，向右下方倾斜6、经济学家根据与的程度，把现实中的市场分为、、、和四种类型。
竞争，垄断，完全竞争，完全垄断，垄断竞争，寡头垄断7、完全垄断市场上的厂商数量是。
1二、判断题1、在完全垄断市场上，一家厂商就是一个行业2、垄断竞争市场上的产量高于完全垄断市场上，价格却低于完全垄断市场3、在完全竞争市场上，个别厂商销售量的变动会影响市场价格的变动4、垄断对社会有百害而无一利，所以，各国都反对垄断5、如果垄断者实行完全的价格歧视，他就可以获得所有消费者剩余6、在市场经济中，完全垄断是普遍存在的7、有差别存在就会有垄断8、在完全竞争市场上，当厂商实现了长期均衡时，可获得超额利润9、寡头垄断市场上的产量是由各寡头之间协商确定的10、只有在完全竞争市场上，平均收益才等于边际收益，其他市场上都不存在这种情况11、产品有差别就不会有完全竞争12、在完全竞争市场上，整个行业的需求曲线是一条与横轴平行的线13、在完全竞争市场上，任何一个厂商都可以成为价格的决定者14、引起垄断竞争的基本条件是产品无差别15、由于寡头之间可以进行勾结，所以，他们之间并不存在竞争 16、在完全垄断市场上，边际收益一定大于平均收益三、单选题1、如果以利润最大化为目标的企业的边际收益小于其边际成本，那么，该企业a. 必然处于经济亏损状态b. 必然获得经济利润c. 应该减少其产量d. 应该增加其产量 c2、在长期中，企业会发生的最大经济亏损是a. 零b. 其总成本c. 其可变成本d. 其平均可变成本 a3、如果一个竞争企业生产的产量使价格等于平均总成本，那么a. 将停止营业b. 收支相抵c. 仍然回获得经济利润d. 处于有经济亏损状态 b4、为了使垄断产生，就应该a. 某个行业的产品只有一个供给者b. 这种物品没有相近的替代品c. 限制其他企业进入d. 以上全对 d5、以下都是完全竞争的特征，其中哪一种不是垄断竞争的特征a. 有许多企业b. 企业生产无差别产品c. 企业一利润最大化为目标d. 自由进入 b6、在长期中要维持卡特尔是困难的。
西方经济学简明原理》期末考试题库及答案-第7章 市场失灵及其矫治
一、选择题1.不完全竞争市场中出现无效率资源配置，原因在于产品价格(D)A.高于边际成本B.低于边际成本C.等于边际成本D.都正确2.由于垄断导致无效率，因此任何垄断都必须被消除，这一说法(B)A.肯定正确B.肯定不正确C.可能正确D.基本正确3.某种经济活动有负的外部影响时，该活动的(B)A.私人成本大于社会成本B.私人成本小于社会成本C.私人利益大于社会收益D.私人收益小于社会收益4.在正的外部影响存在的情况下，(D)A.私人成本大于社会成本B.私人成本小于社会成本C.私人利益大于社会收益D.私人收益小于社会收益5.如果一个人只在自己家里抽烟且不再外人面前抽烟，那么，他抽烟（D）A.负的外部影响B.有正的外部影响C.属于消费中的正的外部影响D.没有外部影响6.科斯定理的基本意思是（B）A.人们的贪心可能阻止市场发挥作用；B.交易成本的存在有可能阻止市场发挥；C.只要产权明晰，市场就能够保证效率；D.只有负的外部影响有可能导致市场失灵。
7.当正的外部影响存在时，市场决定的产量将会（B）A.大于社会理想产量B.小于社会理想产量C.等于社会理想产量D.都可能8.下列物品最有可能是公共物品的是（A）A.公海上的一个灯塔B.国家森林公园内树上的果C.故宫博物院内的国宝D.大熊猫9.一般来说，公共物品的生产低于社会理想的水平，可能的原因在于（D）A.人们不愿意说真话B.“搭便车”的倾向C.人们的觉悟不高D.上面的说法都说得过去10.信息不对称导致市场失灵是因为（D）A.消费者无法识别好的产品或服务；B.劣质产品对优质产品有负的外部影响；C.一块臭肉坏了一锅汤；D.上述说法都说得过去。
11.洛伦兹曲线越是向横轴凸出（A）A、基尼系数就越大，收入就越不平等B、基尼系数就越大，收入就越平等C、基尼系数就越小，收入就越不平等D、基尼系数就越小，收入就越平等12.如果上游工厂污染了下游居民的饮水，按照科斯定理（ B ），问题即可妥善解决。
《经济学原理》课后作业题,第6-8章
第六章1．已知产量为8个单位时，总成本为80元，当产量增加到9个单位时，平均成本为11元，那么此时的边际成本为（）。
A1元B 19元C 88元D 20元2．企业购买生产要素所引起的费用是（）。
A隐性成本B 显性成本C 变动成本D 经济成本3．短期平均成本曲线呈U型的原因是（）。
A外部经济问题B 内部经济问题C 规模收益问题D 边际收益（报酬）问题4．厂商的长期平均成本曲线呈U型的原因是（）。
A外部经济问题B 外部不经济问题C 规模经济问题D 边际收益问题5．以下说法正确的是（）。
A MC大于AC时，AC下降B MC小于AC时，AC下降C MC等于AC时，AC下降D MC等于AC时，AC达到最低点6．随着产量的增加，固定成本（）。
A增加B 不变C 减少D 先增后减7．随着产量的增加，平均固定成本（）。
A在开始时间少，然后趋于增加，B 一直趋于减少C 一直趋于增加D 在开始时增加，然后趋于减少8．边际成本曲线与平均成本曲线的相交点是（）。
A边际成本曲线的最低点B 平均成本曲线的最低点C 平均成本曲线下降阶段的任何一点D 边际成本曲线的最高点9．固定成本是指（）。
A厂商在短期内必须支付的不能调整的生产要素的费用B 厂商增加产量所要增加的费用C 厂商购进生产要素时所要支付的费用D 厂商在短期内必须支付的可能调整的生产要素的费用10．已知产量为500单位时，平均成本为2元，当产量增加到550单位时，平均成本等于2.5元，在这一产量变化范围内，边际成本（）。
A随着产量的增加而增加，并小于平均成本B 随着产量的增加而减少，并大于平均成本C 随着产量的增加而减少，并小于平均成本D 随着产量的增加而增加，并大于平均成本11．某厂商生产5件衣服的总成本为1500元，其中厂房和机器折旧为500元，工人工资及原材料费用为1000元，那么平均可变成本为（）。
A300元B 100元C 200元D 500元，12．全部成本等于（）。
经济学原理曼昆课后答案chapter7
Problems and Applications1. If an early freeze in California sours the lemon crop, the supply curve for lemons shiftsto the left, as shown in Figure 7-5. The result is a rise in the price of lemons and adecline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 7-5In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, as shown in Figure 7-6. The result is a rise in the price of lemonade and a decline in consumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumer surplus in one market often has effects on consumer surplus in other markets.Figure 7-62. A rise in the demand for French bread leads to an increase in producer surplus in themarket for French bread, as shown in Figure 7-7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7-7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 7-8. As a result, the price of flour rises, increasing producer surplus from area D to D + E + F. Note that an event that affects producer surplus in onemarket leads to effects on producer surplus in related markets.Figure 7-83. a. Bert’s demand schedule is:Price Quantity DemandedMore than $7 0$5 to $7 1$3 to $5 2$1 to $3 3$1 or less 4Bert’s demand curve is shown in Figure 7-9.Figure 7-9b. When the price of a bottle of water is $4, Bert buys two bottles of water. Hisconsumer surplus is shown as area A in the figure. He values his first bottle ofwater at $7, but pays only $4 for it, so has consumer surplus of $3. He valueshis second bottle of water at $5, but pays only $4 for it, so has consumersurplus of $1. Thus Bert’s total consumer surplus is $3 + $1 = $4, which isthe area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottlesof water, an increase of one. His consumer surplus consists of both areas Aand B in the figure, an increase in the amount of area B. He gets consumersurplus of $5 from the first bottle ($7 value minus $2 price), $3 from thesecond bottle ($5 value minus $2 price), and $1 from the third bottle ($3 valueminus $2 price), for a total consumer surplus of $9. Thus consumer surplusrises by $5 (which is the size of area B) when the price of a bottle of water fallsfrom $4 to $2.4. a. Ernie’s supply schedule for water is:Price Quantity SuppliedMore than $7 4$5 to $7 3$3 to $5 2$1 to $3 1Less than $1 0Ernie’s supply curve is shown in Figure 7-10.Figure 7-10b. When the price of a bottle of water is $4, Ernie sells two bottles of water. Hisproducer surplus is shown as area A in the figure. He receives $4 for his firstbottle of water, but it costs only $1 to produce, so Ernie has producer surplusof $3. He also receives $4 for his second bottle of water, which costs $3 toproduce, so he has producer surplus of $1. Thus Ernie’s total producersurplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottlesof water, an increase of one. His producer surplus consists of both areas Aand B in the figure, an increase by the amount of area B. He gets producersurplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the secondbottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5price), for a total producer surplus of $9. Thus producer surplus rises by $5(which is the size of area B) when the price of a bottle of water rises from $4 to$6.5. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantitydemanded and supplied are:Only a price of $4 brings supply and demand into equilibrium, with anequilibrium quantity of 2.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shownin problems 3 and 4. Total surplus is $4 + $4 = $8.c. If Ernie produced one fewer bottle, his producer surplus would decline to $3,as shown in problem 4. If Bert consumed one fewer bottle, his consumersurplus would decline to $3, as shown in problem 3. So total surplus woulddecline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but theprice is only $4, so his producer surplus would decline by $1. If Bertconsumed one additional bottle of water, his value would be $3, but the priceis $4, so his consumer surplus would decline by $1. So total surplus declinesby $1 + $1 = $2.精品文档6. a. The effect of falling production costs in the market for stereos results in a shiftto the right in the supply curve, as shown in Figure 7-11. As a result, theequilibrium price of stereos declines and the equilibrium quantity increases.b. The decline in the price of stereos increases consumer surplus from area A to A+ B + C + D, an increase in the amount B + C + D. Prior to the shift in supply,producer surplus was areas B + E (the area above the supply curve and belowthe price). After the shift in supply, producer surplus is areas E + F + G. Soproducer surplus changes by the amount F + G - B, which may be positive ornegative. The increase in quantity increases producer surplus, while thedecline in the price reduces producer surplus. Since consumer surplus risesby B + C + D and producer surplus rises by F + G - B, total surplus rises by C +D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curvebenefits consumers most. To take the most dramatic case, suppose thesupply curve were horizontal, as shown in Figure 7-12. Then there is noproducer surplus at all. Consumers capture all the benefits of fallingproduction costs, with consumer surplus rising from area A to area A + B.Figure 7-11精品文档Figure 7-127. Figure 7-13 shows supply and demand curves for haircuts. Supply equals demand ata quantity of three haircuts and a price between $4 and $5. Firms A, C, and D shouldcut the hair of Sally Jessy, Jerry, and Montel. Oprah’s willingness to pay is too low and firm B’s costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which totals $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 valueminus $4 cost for the third).Figure 7-13精品文档8. a. The effect of falling production costs in the market for computers results in ashift to the right in the supply curve, as shown in Figure 7-14. As a result, theequilibrium price of computers declines and the equilibrium quantity increases.The decline in the price of computers increases consumer surplus from area Ato A + B + C + D, an increase in the amount B + C + D.Figure 7-14Prior to the shift in supply, producer surplus was areas B + E (the area abovethe supply curve and below the price). After the shift in supply, producersurplus is areas E + F + G. So producer surplus changes by the amount F + G- B, which may be positive or negative. The increase in quantity increasesproducer surplus, while the decline in the price reduces producer surplus.Since consumer surplus rises by B + C + D and producer surplus rises by F + G- B, total surplus rises by C + D + F + G.Figure 7-15b. Since adding machines are substitutes for computers, the decline in the priceof computers means that people substitute computers for adding machines,shifting the demand for adding machines to the left, as shown in Figure 7-15.The result is a decline in both the equilibrium price and equilibrium quantity of adding machines. Consumer surplus in the adding-machine market changes from area A + B to A + C, a net gain of C - B. Producer surplus changes from area C + D + E to area E, a net loss of C + D. Adding machine producers are sad about technological advance in computers because their producer surplus declines.c. Since software and computers are complements, the decline in the price andincrease in the quantity of computers means that people’s demand forsoftware increases, shifting the demand for software to the right, as shown in Figure 7-16. The result is an increase in both the price and quantity ofsoftware. Consumer surplus in the software market changes from B + C to A + B, a net increase of A - C. Producer surplus changes from E to C + D + E, an increase of C + D, so software producers should be happy about thetechnological progress in computers.d. Yes, this analysis helps explain why Bill Gates is one the world’s richest men,since his company produces a lot of software that’s a complement withcomputers and there has been tremendous technological advance incomputers.Figure 7-169. a. Figure 7-17 illustrates the demand for medical care. If each procedure has aprice of $100, quantity demanded will be Q1 procedures.Figure 7-17b. If consumers pay only $20 per procedure, the quantity demanded will be Q2procedures. Since the cost to society is $100, the number of proceduresperformed is too large to maximize total surplus. The quantity thatmaximizes total surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers getprocedures whose value is less than the cost of producing them. As a result,the economy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost ofthe procedure. But this would require eliminating insurance. Anotherpossibility would be that the insurance company, which pays most of themarginal cost of the procedure ($80, in this case) could decide whether theprocedure should be performed. But the insurance company doesn’t get thebenefits of the procedure, so its decisions may not reflect the value to theconsumer.10. a. Figure 7-18 illustrates the effect of the drought. The supply curve shifts tothe left, leading to a rise in the equilibrium price from P1 to P2 and a decline inthe equilibrium quantity from Q1 to Q2.Figure 7-18b. If the price of water is not allowed to change, there will be an excess demandfor water, with the shortage shown on the figure as the difference between Q1and Q3.c. The system for allocating water is inefficient because it no longer allocateswater to those who value it most highly. Some people who value water atmore than its cost of production will be unable to obtain it, so society’s totalsurplus isn’t maximized.The allocation system seems unfair as well. Water is allocated simply on pastusage, rewarding past wastefulness. If a family’s demand for water increases,say because of an increase in family size, the policy doesn’t allow them toobtain more water. Poor families, who probably used water mostly fornecessary uses like drinking, would suffer more than wealthier families whowould have to cut back only on luxury uses of water like operating backyardfountains and pools. However, the policy also keeps the price of water lower, which benefits poor families, since otherwise more of their family budgetwould have to go for water.d. If the city allowed the price of water to rise to its equilibrium price P2, theallocation would be more efficient. Quantity supplied would equal quantitydemanded and there would be no shortage. Total surplus would bemaximized.Whether the market allocation would be more or less fair than theproportionate reduction in water under the old policy is difficult to say, but it is likely to be more fair. Notice that the quantity supplied would be higher (Q2) in this case than under the water restrictions (Q3), so there’s less reduction in water usage. To make the market solution even more fair, the governmentcould provide increased tax relief or welfare payments for poor families whosuffer from paying the higher water prices.。
曼昆经济学原理第七课后题及答案
答：按 1992 年的价格衡量， 1997 年的实际收入是 72419．7 亿元。
二十三章1 下列每种交易会影响 CDP 的哪一部分 (如果有影响的话 ) 并解释之。
A ． 家庭购买了一台新冰箱。
答：家庭购买了一台新冰箱会增加GDP 中的消费 (C) 部分，因为家庭用于家用电器的支出计算在消费的耐用品类中。
B ． 杰妮姑妈买了一所新房子。
答：杰妮姑妈买了一所新房子会增加 GDP 中的投资 (1) 部分，因为家庭住宅能长期供人 居住，提供服务。
它比一般耐用消费品的使用寿命更长，因此把住宅房屋的投资计算在 投资中。
C.福特汽车公司由其存货中出售了一部雷鸟牌汽车。
答：福利汽车公司由其存货中出售了一部雷鸟牌汽车会减少现期GDP 中的投资， 因为销售 中间物品存货时，企业的存货投资是负的，因而减少了当期的 GDP 。
C ． 你买了一个比萨饼。
答：我买了一个比萨饼会增加 GDP 中的消费 (C) ，因为我用于购买食品的支出计算在消 费的非耐用品类中。
D ． 加利福尼亚重新铺设了 101 号高速公路。
答：加利福尼亚重新铺设了 101 号高速公路增加了 GDP 中的政府购买 (G) ，因为修建高 速公路是政府的行为。
E ． 你的父母购买了一瓶法国红酒。
答：我的父母购买了一瓶法国红酒会减少 GDP 中的净出口 (NX) ，因为法国红酒是进口食品，它的购买增加了美国的进口。
F ． 本田公司扩大其在俄亥俄州马利斯维尔的工厂。
答：本田公司扩大其在俄亥俄州马利斯维尔的工厂增加了GDP 中的净出口 (NX) ，因为本 田公司是一家日本企业，它在美国的投资减少了美国对日本本田汽车的进口，使 NX 增 加2． GDP 组成部分中的“政府购买”并不包括用于社会保障这类转移支付的支出。
想想GDP 的定义，解释为什么转移支付不包括在政府购买内答： 因为转移支付并不是要交换现在生产的物品或劳务， 从宏观经济的角度看， 转移支付就像税收和回扣一样。
微观经济学课后习题答案第七章完整版
微观经济学课后习题答案第七章HEN system office room 【HEN16H-HENS2AHENS8Q8-HENH1688】第七章 复习思考题 参考答案1、为什么垄断厂商的需求曲线是向右下方倾斜的？并解释相应的TR 曲线、AR 曲线和MR 曲线的特征以及相互关系。
解答：垄断厂商所面临的需求曲线是向右下方倾斜的，其理由主要有两点：第一，垄断厂商所面临的需求曲线就是市场的需求曲线，而市场需求曲线一般是向右下方倾斜的，所以垄断厂商的需求量与价格成反方向的变化。
第二，假定厂商的销售量等于市场的需求量，那么，垄断厂商所面临的向右下方倾斜的需求曲线表示垄断厂商可以通过调整销售量来控制市场的价格，即垄断厂商可以通过减少商品的销售量来提高市场价格，也可以通过增加商品的销售量来降低市场价格。
关于垄断厂商的TR 曲线、AR 曲线和MR 曲线的特征以及相互关系，以图7-1加以说明：第一，平均收益AR 曲线与垄断厂商的向右下方倾斜的d 需求曲线重叠。
因为，在任何的销售量上，都是P=AR 。
第二，边际收益MR 曲线是向右下方倾斜的，且位置低于AR 曲线。
其原因在于AR 曲线是一条下降的曲线。
此外，在线性需求曲线的条件下，AR 曲线和MR 曲线的纵截距相同，而且MR 曲线的斜率的绝对值是AR 曲线的斜率的绝对值的两倍。
第三，由于MR 值是TR 曲线的斜率，即dQdTR MR =，所以，当MR>0时，TR 曲线是上升的；当MR ＜0时，TR 曲线是下降的；当MR=0时，TR 曲线达极大值。
图 7-1 垄断竞争厂商的AR 与TR 之间的关系2、根据图7-22中线性需求曲线d 和相应的边际收益曲线MR ，试求：（1）A 点所对应的MR 值；（2）B 点所对应的MR 值。
解答：（1）根据需求的价格点弹性的几何意义，可得A 点的需求的价格弹性为：25)515(=-=d e ， 或者，2)23(2=-=d e ，根据)11(d e P MR -=，则A 点的MR 值为：MR=2×（2×1/2）=1。
曼昆微观经济学课后练习英文答案(第七章)
WHAT’S NEW IN THE SIXTH EDITION:There are no major changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:➢ the link between buyers’ willingness to pay for a good and the demand curve.➢ how to define and measure consumer surplus.➢ the link between sellers’ costs of producing a good and the supply curve.➢ how to define and measure producer surplus.➢ that the equilibrium of supply and demand maximizes total surplus in a market.CONTEXT AND PURPOSE:Chapter 7 is the first chapter in a three-chapter sequence on welfare economics and market efficiency. Chapter 7 employs the supply and demand model to develop consumer surplus and producer surplus as a measure of welfare and market efficiency. These concepts are then utilized in Chapters 8 and 9 to determine the winners and losers from taxation and restrictions on international trade.The purpose of Chapter 7 is to develop welfare economics —the study of how the allocation ofresources affects economic well-being. Chapters 4 through 6 employed supply and demand in a positive framework, which focused on the question, “What is the equilibrium price and quantity in a market?” This chapter now addresses the normative question, “Is the equ ilibrium price and quantity in a market the best possible solution to the resource allocation problem, or is it simply the price and quantity thatbalance supply and demand?” Students will discover that under most circumstances the equilibrium price and quantity is also the one that maximizes welfare.7CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETSKEY POINTS:• Consumer surplus equals buyers’ willingness to pay for a good minus the amount they actually pay for it, and it measures the benefit buyers get from participating in a market. Consumer surplus can be computed by finding the area below the demand curve and above the price.• Producer surplus equals the amount sellers receive for their goods minus their costs of production, and it measures the benefit sellers get from participating in a market. Producer surplus can be computed by finding the area below the price and above the supply curve.•An allocation of resources that maximizes the sum of consumer and producer surplus is said to be efficient. Policymakers are often concerned with the efficiency, as well as the equality, of economic outcomes.• The equilibrium of supply and demand maximizes the sum of consumer and producer surplus. That is,the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently.• Markets do not allocate resources efficiently in the presence of market failures such as market poweror externalities.CHAPTER OUTLINE:I. Definition of welfare economics: the study of how the allocation of resources affectseconomic well-being.II. Consumer SurplusA. Willingness to Pay1. Definition of willingness to pay: the maximum amount that a buyer will pay for agood.2. Example: You are auctioning a mint-condition recording of Elvis Presley’s first album. Fourbuyers show up. Their willingness to pay is as follows:If the bidding goes to slightly higher than $80, all buyers drop out except forJohn. Because John is willing to pay more than he has to for the album, hederives some benefit from participating in the market.3. Definition of consumer surplus: the amount a buyer is willing to pay for a goodminus the amount the buyer actually pays for it.4. Note that if you had more than one copy of the album, the price in the auction would end upbeing lower (a little over $70 in the case of two albums) and both John and Paul would gain consumer surplus.B. Using the Demand Curve to Measure Consumer Surplus1. We can use the information on willingness to pay to derive a demand curve for the rare ElvisPresley album.PriceBuyersQuantity DemandedMore than $100 None 0 $80 to $100 John1 $70 to $80 John, Paul2 $50 to $70 John, Paul, George3 $50 or lessJohn, Paul, George, Ringo42. At any given quantity, the price given by the demand curve reflects the willingness to pay ofthe marginal buyer . Because the demand curve shows the buyers’ willingness to pay, we can use the demand curve to measure consumer surplus.Figure 1 “This represents the demand curve for the time machine. Consumer surplus is the difference between what consumers are willing to pay and the amount they actually have to pay. The market price will deter mine who uses the time machine and how much surplus they keep.”“If the price of a time machine ride was $500, three rides would be sold—one to Scott, one to Carol, and one to Steve. Jeanne is not willing to pay $500, so she wouldn’t time travel.”“We c an calculate the consumer surplus of three time trips. Scott would pay $3,000 but only pays $500, leaving $2,500 of net benefits.” (Put these numbers on the board.) “Carol has net benefits of $2,000. Steve has $300 in net benefits. Adding up these net savings gives $4,800 in consumer surplus.”Points for DiscussionThe consumer surplus depends on a good’s selling price and the number of consumers who are willing to purchase the good at that price. The lower the price, the greater the consumer surplus.3. Consumer surplus can be measured as the area below the demand curve and above the price. C. How a Lower Price Raises Consumer Surplus1. As price falls, consumer surplus increases for two reasons.a. Those already buying the product will receive additional consumer surplus because theyare paying less for the product than before (area A on the graph).b. Because the price is now lower, some new buyers will enter the market and receiveconsumer surplus on these additional units of output purchased (area B on the graph).D. What Does Consumer Surplus Measure?1. Remember that consumer surplus is the difference between the amount that buyers arewilling to pay for a good and the price that they actually pay.2. Thus, it measures the benefit that consumers receive from the good as the buyersthemselves perceive it.Figure 2Figure 3It is important to stress that consumer surplus is measured in monetary terms. Consumer surplus gives us a way to place a monetary cost on inefficient market outcomes (due to government involvement or market failure).III. Producer SurplusA. Cost and the Willingness to Sell1. Definition of cost: the value of everything a seller must give up to produce a good .2. Example: You want to hire someone to paint your house. You accept bids for the work fromfour sellers. Each painter is willing to work if the price you will pay exceeds her opportunity cost. (Note that this opportunity cost thus represents willingness to sell.) The costs are:3. Bidding will stop when the price gets to be slightly below $600. All sellers will drop out exceptfor Grandma. Because Grandma receives more than she would require to paint the house, she derives some benefit from producing in the market.4. Definition of producer surplus: the amount a seller is paid for a good minus theseller’s cost of providing it.5. Note that if you had more than one house to paint, the price in the auction would end upbeing higher (a little under $800 in the case of two houses) and both Grandma and Georgia would gain producer surplus.ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price ceilings from Chapter 6. Redraw the market for two-bedroom apartments in your town. Draw in a price ceiling below the equilibrium price.Then go through:▪ consumer surplus before the price ceiling is put into place. ▪ consumer surplus after the price ceiling is put into place.B. Using the Supply Curve to Measure Producer Surplus1. We can use the information on cost (willingness to sell) to derive a supply curve for housepainting services.Price Sellers Quantity Supplied$900 or more Mary, Frida, Georgia, Grandma 4$800 to $900 Frida, Georgia, Grandma 3$600 to $800 Georgia, Grandma 2$500 to $600 Grandma 1less than $500 None 02. At any given quantity, the price given by the supply curve represents the cost of the marginalseller. Because the supply curve shows the sellers’ cost (willingness to sell), we can use the supply curve to measure producer surplus.3. Producer surplus can be measured as the area above the supply curve and below the price. Figure 4Figure 5C. How a Higher Price Raises Producer Surplus1. As price rises, producer surplus increases for two reasons.a. Those already selling the product will receive additional producer surplus because theyare receiving more for the product than before (area C on the graph).b. Because the price is now higher, some new sellers will enter the market and receiveproducer surplus on these additional units of output sold (area D on the graph).D. Producer surplus is used to measure the economic well-being of producers, much like consumersurplus is used to measure the economic well-being of consumers.Figure 6ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price floors from Chapter 6. Redraw the market for an agriculturalproduct such as corn. Draw in a price support above the equilibrium price.Then go through:▪ producer surplus before the price support is put in place.▪ producer surplus after the price support is put in place.Make sure that you discuss the cost of the price support to taxpayers.Pretty Woman, Chapter 6. Vivien (Julia Roberts) and Edward (Richard Gere)negotiate a price. Afterward, Vivien reveals she would have accepted a lower price,while Edward admits he would have paid more. If you have done a good job ofintroducing consumer and producer surplus, you will see the light bulbs go off aboveyour students’ heads as they watch this clip.IV. Market EfficiencyA. The Benevolent Social Planner1. The economic well-being of everyone in society can be measured by total surplus, which isthe sum of consumer surplus and producer surplus:Total Surplus = Consumer Surplus + Producer SurplusTotal Surplus = (Value to Buyers – Amount Paid by Buyers) + (Amount Received by Sellers – Cost to Sellers)Because the Amount Paid by Buyers = Amount Received by Sellers:2. Definition ofefficiency: the property of a resource allocation of maximizing thetotal surplus received by all members of society .3. Definition of equality: the property of distributing economic prosperity uniformlythe members of society .B. Evaluating the Market EquilibriumTotal Surplus = Value to Buyers Cost to Sellers Figure 7Now might be a good time to point out that many government policies involve atrade-off between efficiency and equity. When you evaluate government policies, like price ceilings or floors, you can explain them in terms of equity and efficiency.1. At the market equilibrium price:a. Buyers who value the product more than the equilibrium price will purchase the product;those who do not, will not purchase the product. In other words, the free marketallocates the supply of a good to the buyers who value it most highly, as measured bytheir willingness to pay.b. Sellers whose costs are lower than the equilibrium price will produce the product; thosewhose costs are higher, will not produce the product. In other words, the free marketallocates the demand for goods to the sellers who can produce it at the lowest cost.2. Total surplus is maximized at the market equilibrium.Figure 8a. At any quantity of output smaller than the equilibrium quantity, the value of the productto the marginal buyer is greater than the cost to the marginal seller so total surpluswould rise if output increases.b. At any quantity of output greater than the equilibrium quantity, the value of the productto the marginal buyer is less than the cost to the marginal seller so total surplus wouldrise if output decreases.3. Note that this is one of the reasons that economists believe Principle #6: Markets are usuallya good way to organize economic activity.It would be a good idea to remind students that there are circumstances when themarket process does not lead to the most efficient outcome. Examples includesituations such as when a firm (or buyer) has market power over price or when thereare externalities present. These situations will be discussed in later chapters.C. In the News: Ticket Scalping1. Ticket scalping is an example of how markets work to achieve an efficient outcome.2. This article from The Boston Globe descri bes economist Chip Case’s experience with ticketscalping.D. Case Study: Should There Be a Market in Organs?1. As a matter of public policy, people are not allowed to sell their organs.a. In essence, this means that there is a price ceiling on organs of $0.b. This has led to a shortage of organs.2. The creation of a market for organs would lead to a more efficient allocation of resources,but critics worry about the equity of a market system for organs.V. Market Efficiency and Market FailureA. To conclude that markets are efficient, we made several assumptions about how markets worked.1. Perfectly competitive markets.2. No externalities.B. When these assumptions do not hold, the market equilibrium may not be efficient.C. When markets fail, public policy can potentially remedy the situation.SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1 and the consumersurplus that results from that price is denoted CS. Consumer surplus is the amount a buyer iswilling to pay for a good minus the amount the buyer actually pays for it. It measures thebenefit to buyers of participating in a market.Figure 1 Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1 and the producersurplus that results from that price is denoted PS. Producer surplus is the amount sellers arepaid for a good minus the sellers’ cost of providing it (measured by the supply curve). Itmeasures the benefit to sellers of participating in a market.Figure 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1, consumersurplus is CS, and producer surplus is PS. Producing more turkeys than the equilibriumquantity would lower total surplus because the value to the marginal buyer would be lowerthan the cost to the marginal seller on those additional units.Questions for Review1. The price a buyer is willing to pay, consumer surplus, and the demand curve are all closelyrelated. The height of the demand curve represents the willingness to pay of the buyers.Consumer surplus is the area below the demand curve and above the price, which equals theprice that each buyer is willing to pay minus the price actually paid.2. Sellers' costs, producer surplus, and the supply curve are all closely related. The height of thesupply curve represents the costs of the sellers. Producer surplus is the area below the priceand above the supply curve, which equals the price received minus each seller's costs ofproducing the good.Figure 43. Figure 4 shows producer and consumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum of consumersurplus and producer surplus. But efficiency may not be the only goal of economicpolicymakers; they may also be concerned about equity the fairness of the distribution ofwell-being.5. The invisible hand of the marketplace guides the self-interest of buyers and sellers intopromoting general economic well-being. Despite decentralized decision making and self-interested decision makers, free markets often lead to an efficient outcome.6. Two types of market failure are market power and externalities. Market power may causemarket outcomes to be inefficient because firms may cause price and quantity to differ fromthe levels they would be under perfect competition, which keeps total surplus from beingmaximized. Externalities are side effects that are not taken into account by buyers and sellers.As a result, the free market does not maximize total surplus.Problems and Applications1. a. Consumer surplus is equal to willingness to pay minus the price paid. Therefore,Melissa’s willingness to pay must be $200 ($120 + $80).b. Her consumer surplus at a price of $90 would be $200 − $90 = $110.c. If the price of an iPod was $250, Melissa would not have purchased one because theprice is greater than her willingness to pay. Therefore, she would receive no consumersurplus.2. If an early freeze in California sours the lemon crop, the supply curve for lemons shifts to theleft, as shown in Figure 5. The result is a rise in the price of lemons and a decline inconsumer surplus from A + B + C to just A. So consumer surplus declines by the amount B +C.Figure 5 Figure 6In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, asshown in Figure 6. The result is a rise in the price of lemonade and a decline in consumersurplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumersurplus in one market often has effects on consumer surplus in other markets.3. A rise in the demand for French bread leads to an increase in producer surplus in the marketfor French bread, as shown in Figure 7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 8. As a result, the price of flour rises, increasing producer surplus from area D to D + E + F. Note that an event that affects producer surplus in one market leads to effects on producer surplus in related markets.Figure 84. a. Bert’s demand schedule is:Price Quantity DemandedMore than $7 0$5 to $7 1$3 to $5 2$1 to $3 3$1 or less 4Bert’s demand curve is shown in Figure 9.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. His consumersurplus is shown as area A in the figure. He values his first bottle of water at $7, butpays only $4 for it, so has consumer surplus of $3. He values his second bottle of water at $5, but pays only $4 for it, so has consumer surplus of $1. Thus Bert’s total consumer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottles of water,an increase of one. His consumer surplus consists of both areas A and B in the figure, an increase in the amount of area B. He gets consumer surplus of $5 from the first bottle($7 value minus $2 price), $3 from the second bottle ($5 value minus $2 price), and $1 from the third bottle ($3 value minus $2 price), for a total consumer surplus of $9. Thus consumer surplus rises by $5 (which is the size of area B) when the price of a bottle ofwater falls from $4 to $2.5. a. Ernie’s supply schedule for water is:Price Quantity SuppliedMore than $7 4$5 to $7 3$3 to $5 2$1 to $3 1Less than $1 0Ernie’s supply curve is shown in Figure 10.Figure 10b. When the price of a bottle of water is $4, Ernie sells two bottles of water. His producersurplus is shown as area A in the figure. He receives $4 for his first bottle of water, but itcosts only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs $3 to produce, so he has producer surplus of $1.Thus Ernie’s total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottles of water,an increase of one. His producer surplus consists of both areas A and B in the figure, anincrease by the amount of area B. He gets producer surplus of $5 from the first bottle($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thusproducer surplus rises by $5 (which is the size of area B) when the price of a bottle ofwater rises from $4 to $6.6. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantity demanded andsupplied are:Price Quantity Supplied Quantity Demanded$2 1 3$4 2 2$6 3 1Only a price of $4 brings supply and demand into equilibrium, with an equilibriumquantity of two.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shown inProblems 3 and 4 above. Total surplus is $4 + $4 = $8.c. If Ernie produced one less bottle, his producer surplus would decline to $3, as shown inProblem 4 above. If Bert consumed one less bottle, his consumer surplus would declineto $3, as shown in Problem 3 above. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but the price isonly $4, so his producer surplus would decline by $1. If Bert consumed one additionalbottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.7. a. The effect of falling production costs in the market for stereos results in a shift to theright in the supply curve, as shown in Figure 11. As a result, the equilibrium price ofstereos declines and the equilibrium quantity increases.Figure 11b. The decline in the price of stereos increases consumer surplus from area A to A + B + C+ D, an increase in the amount B + C + D. Prior to the shift in supply, producer surpluswas areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amountF +G – B, which may be positive or negative. The increase in quantity increasesproducer surplus, while the decline in the price reduces producer surplus. Becauseconsumer surplus rises by B + C + D and producer surplus rises by F + G – B, totalsurplus rises by C + D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curve benefitsconsumers most. To take the most dramatic case, suppose the supply curve werehorizontal, as shown in Figure 12. Then there is no producer surplus at all. Consumerscapture all the benefits of falling production costs, with consumer surplus rising fromarea A to area A + B.Figure 128. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at a quantityof three haircuts and a price between $4 and $5. Firms A, C, and D should cut the hair of Ellen, Jerry, and Phil. Oprah’s willingness to pay is too low and firm B’s costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which totals $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 value minus $4 cost for the third).Figure 139. a. The effect of falling production costs in the market for computers results in a shift to theright in the supply curve, as shown in Figure 14. As a result, the equilibrium price ofcomputers declines and the equilibrium quantity increases. The decline in the price ofcomputers increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D.Figure 14 Figure 15Prior to the shift in supply, producer surplus was areas B + E (the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G.So producer surplus changes by the amount F + G – B, which may be positive ornegative. The increase in quantity increases producer surplus, while the decline in theprice reduces producer surplus. Because consumer surplus rises by B + C + D andproducer surplus rises by F + G – B, total surplus rises by C + D + F + G.b. Because typewriters are substitutes for computers, the decline in the price of computersmeans that people substitute computers for typewriters, shifting the demand fortypewriters to the left, as shown in Figure 15. The result is a decline in both theequilibrium price and equilibrium quantity of typewriters. Consumer surplus in thetypewriter market changes from area A + B to A + C, a net change of C – B. Producersurplus changes from area C + D + E to area E, a net loss of C + D. Typewriterproducers are sad about technological advances in computers because their producersurplus declines.c. Because software and computers are complements, the decline in the price and increasein the quantity of computers means that the demand for software increases, shifting the demand for software to the right, as shown in Figure 16. The result is an increase in both the price and quantity of software. Consumer surplus in the software market changesfrom B + C to A + B, a net change of A – C. Producer surplus changes from E to C + D + E, an increase of C + D, so software producers should be happy about the technological progress in computers.Figure 16d. Yes, this analysis helps explain why Bill Gates is one the world’s richest people, becausehis company produces a lot of software that is a complement with computers and therehas been tremendous technological advance in computers.10. a. With Provider A, the cost of an extra minute is $0. With Provider B, the cost of an extraminute is $1.b. With Provider A, my friend will purchase 150 minutes [= 150 – (50)(0)]. With Provider B,my friend would purchase 100 minutes [= 150 – (50)(1)].c. With Provider A, he would pay $120. The cost would be $100 with Provider B.Figure 17d. Figure 17 shows the friend’s demand. With Provider A, he buys 150 minu tes and hisconsumer surplus is equal to (1/2)(3)(150) – 120 = 105. With Provider B, his consumersurplus is equal to (1/2)(2)(100) = 100.e. I would recommend Provider A because he receives greater consumer surplus.11. a. Figure 18 illustrates the demand for medical care. If each procedure has a price of $100,quantity demanded will be Q1 procedures.Figure 18b. If consumers pay only $20 per procedure, the quantity demanded will be Q2 procedures.Because the cost to society is $100, the number of procedures performed is too large to maximize total surplus. The quantity that maximizes total surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers get procedures whosevalue is less than t he cost of producing them. As a result, the economy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost of theprocedure. But this would require eliminating insurance. Another possibility would be that the insurance company, which pays most of the marginal cost of the procedure ($80, in this case) could decide whether the procedure should be performed. But the insurance company does not get the benefits of the procedure, so its decisions may not reflect the value to the consumer.。
西方经济学微观部分第七章课后答案
第七章 不完全竞争的市场1、根据图1-31即教材第257页图7-22中线性需求曲线d 和相应的边际收益曲线MR,试求：1A 点所对应的MR 值； 2B 点所对应的MR 值.解答：1根据需求的价格点弹性的几何意义,可得A 点的需求的价格弹性为：25)515(=-=d e 或者 2)23(2=-=d e 再根据公式MR=Pd e 11-,则A 点的MR 值为：MR=2×2×1/2=12与1类似,根据需求的价格点弹性的几何意义,可得B 点的需求的价格弹性为：21101015=-=d e 或者 21131=-=d e再根据公式MR=d e 11-,则B 点的MR 值为：)2/111(1-⨯=MR =-12、图1-39即教材第257页图7-23是某垄断厂商的长期成本曲线、需求曲线和收益曲线.试在图中标出：1长期均衡点及相应的均衡价格和均衡产量；2长期均衡时代表最优生产规模的SAC曲线和SMC曲线；3长期均衡时的利润量.解答：本题的作图结果如图1-40所示：1长期均衡点为E点,因为,在E点有MR=LMC.由E点出发,均衡价格为P0,均衡数量为Q0 .2长期均衡时代表最优生产规模的SAC曲线和SMC曲线如图所示.在Q0 的产量上,SAC曲线和SMC曲线相切；SMC曲线和LMC曲线相交,且同时与MR曲线相交.3长期均衡时的利润量有图中阴影部分的面积表示,即л=ARQ0-SACQ0Q03、已知某垄断厂商的短期成本函数为STC=0.1Q3-6Q2+14Q+3000,反需求函数为P=150-3.25Q求：该垄断厂商的短期均衡产量与均衡价格.解答：因为SMC=dSTC/dQ=0.3Q2-12Q+140且由TR=P=150-3.25=150Q-3.25Q2得出MR=150-6.5Q根据利润最大化的原则MR=SMC0.3Q2-12Q+140=150-6.5Q解得Q=20负值舍去以Q=20代人反需求函数,得P=150-3.25Q=85所以均衡产量为20 均衡价格为854、已知某垄断厂商的成本函数为TC=0.6Q2+3Q+2,反需求函数为P=8-0.4Q.求：1该厂商实现利润最大化时的产量、价格、收益和利润.2该厂商实现收益最大化的产量、价格、收益和利润.3比较1和2的结果.dTC解答：1由题意可得：MC=32.1+=QdQ且MR=8-0.8Q于是,根据利润最大化原则MR=MC有：8-0.8Q=1.2Q+3解得 Q=2.5以Q=2.5代入反需求函数P=8-0.4Q,得：P=8-0.4×2.5=7以Q=2.5和P=7代入利润等式,有：л=TR-TC=PQ-TC=7×0.25-0.6×2.52+2=17.5-13.25=4.25所以,当该垄断厂商实现利润最大化时,其产量Q=2.5,价格P=7,收益TR=17.5,利润л=4.252由已知条件可得总收益函数为： TR=P=8-0.4=8Q-0.4Q2令08.08:,0=-==Q dQdTRdQ dTR即有 解得Q=10 且8.0-=dQdTR＜0 所以,当Q=10时,TR 值达最大值. 以Q=10代入反需求函数P=8-0.4Q,得： P=8-0.4×10=4以Q=10,P=4代入利润等式,有 л=TR-TC=PQ-TC=4×10-0.6×102+3×10+2 =40-92=-52所以,当该垄断厂商实现收益最大化时,其产量Q=10,价格P=4,收益TR=40,利润л=-52,即该厂商的亏损量为52.3通过比较1和2可知：将该垄断厂商实现最大化的结果与实现收益最大化的结果相比较,该厂商实现利润最大化时的产量较低因为2.25<10,价格较高因为7>4,收益较少因为17.5<40,利润较大因为4.25>-52.显然,理性的垄断厂商总是以利润最大化作为生产目标,而不是将收益最大化作为生产目标.追求利润最大化的垄断厂商总是以较高的垄断价格和较低的产量,来获得最大的利润.5．已知某垄断厂商的反需求函数为P=100-2Q+2A ,成本函数为TC=3Q 2+20Q+A,其中,A 表示厂商的广告支出. 求：该厂商实现利润最大化时Q 、P 和A 的值. 解答：由题意可得以下的利润等式： л=P.Q-TC=100-2Q+2A Q-3Q 2+20Q+A =100Q-2Q 2+2A Q-3Q 2-20Q-A =80Q-5Q 2+2A Q-A将以上利润函数лQ,A 分别对Q 、A 求偏倒数,构成利润最大化的一阶条件如下：+-=∂Q dQ1080π2A =0 0121=-=∂∂Q A Aπ求以上方程组的解： 由2得A =Q,代入1得： 80-10Q+20Q=0 Q=10 A=100在此略去对利润在最大化的二阶条件的讨论. 以Q=10,A=100代入反需求函数,得： P=100-2Q+2A =100-2×10+2×10=100所以,该垄断厂商实现利润最大化的时的产量Q=10,价格P=100,广告支出为A=100.6.已知某垄断厂商利用一个工厂生产一种产品,其产品在两个分割的市场上出售,他的成本函数为TC=Q2+40Q,两个市场的需求函数分别为Q1=12-0.1P1,Q2=20-0.4P2.求：1当该厂商实行三级价格歧视时,他追求利润最大化前提下的两市场各自的销售量、价格以及厂商的总利润.2当该厂商在两个市场实行统一的价格时,他追求利润最大化前提下的销售量、价格以及厂商的总利润.3比较1和2的结果.解答：1由第一个市场的需求函数Q1=12-0.1P1可知,该市场的反需求函数为P1=120-10Q1,边际收益函数为MR1=120-20Q1.同理,由第二个市场的需求函数Q2=20-0.4P2可知,该市场的反需求函数为P2=50-2.5Q2,边际收益函数为MR2=50-5Q2.而且,市场需求函数Q=Q1+Q2=12-0.1P+20-0.4P=32-0.5P,且市场反需求函数为P=64-2Q,市场的边际收益函数为MR=64-4Q.dTC.此外,厂商生产的边际成本函数MC=40=Q2+dQ该厂商实行三级价格歧视时利润最大化的原则可以写为MR1=MR2=MC. 于是：关于第一个市场：根据MR1=MC,有：120-20Q1=2Q+40 即 22Q1+2Q2=80关于第二个市场：根据MR2=MC,有：50-5Q2=2Q+40 即 2Q1+7Q2=10由以上关于Q1、Q2的两个方程可得,厂商在两个市场上的销售量分别为：Q1=3.6 Q2=0.4P1=84,P2=49.在实行三级价格歧视的时候,厂商的总利润为：л=TR1+TR2-TC=P1Q1+P2Q2-Q1+Q22-40Q1+Q2=84×3.6+49×0.4-42-40×4=1462当该厂商在两个上实行统一的价格时,根据利润最大化的原则即该统一市场的MR=MC有：64-4Q=2Q+40解得 Q=4以Q=4代入市场反需求函数P=64-2Q,得：P=56于是,厂商的利润为：л=P.Q-TC=56×4-42+40×4=48所以,当该垄断厂商在两个市场上实行统一的价格时,他追求利润最大化的销售量为Q=4,价格为P=56,总的利润为л=48.3比较以上1和2的结果,可以清楚地看到,将该垄断厂商实行三级价格歧视和在两个市场实行统一作价的两种做法相比较,他在两个市场制定不同的价格实行实行三级价格歧视时所获得的利润大于在两个市场实行统一定价时所获得的利润因为146>48.这一结果表明进行三级价格歧视要比不这样做更为有利可图.7、已知某垄断竞争厂商的长期成本函数为LTC=0.001Q3-0.51Q2+200Q；如果该产品的生产集团内所有的厂商都按照相同的比例调整价格,那么,每个厂商的份额需求曲线或实际需求曲线为Ｐ＝238-0.5Ｑ.求：1该厂商长期均衡时的产量与价格.2该厂商长期均衡时主观需求曲线上的需求的价格点弹性值保持整数部分.3如果该厂商的主观需求曲线是线性的,推导该厂商长期均衡时的主观需求的函数.解答：1由题意可得：ＬＡＣ＝ＬTＣ／Ｑ＝0.001Ｑ2－0.51Ｑ+200ＬＭＣ＝dLTC/dQ=0.003Q2-1.02Q+200且已知与份额需求Ｄ曲线相对应的反需求函数为Ｐ＝238-0.5Ｑ.由于在垄断竞争厂商利润最大化的长期均衡时,Ｄ曲线与ＬＡＣ曲线相交因为л＝0,即有ＬＡＣ＝Ｐ,于是有：001Ｑ2-0.51Ｑ+200＝238-0.5Ｑ解得Ｑ＝200负值舍去了以Ｑ＝200代入份额需求函数,得：Ｐ＝238-0.5×200＝138所以,该垄断竞争厂商实现利润最大化长期均衡时的产量Ｑ＝200,价格Ｐ＝138.2由Ｑ＝200代入长期边际成本ＬＭＣ函数,得：ＬＭＣ＝0.003×2002－1.02×200+200＝116因为厂商实现长期利润最大化时必有ＭＲ＝ＬＭＣ,所以,亦有ＭＲ＝116.再根据公式MR=P de 11-,得： 116=138d e 11- 解得d e ≈6所以,厂商长期均衡时主观需求曲线d 上的需求的价格点弹性d e ≈6.3令该厂商的线性的主观需求d 曲线上的需求的函数形式 P=A-BQ,其中,A 表示该线性需求d 曲线的纵截距,-B 表示斜率.下面,分别求A 值和B 值.根据线性需求曲线的点弹性的几何意义,可以有PA P e d -= ,其中,P 表示线性需求d 曲线上某一点所对应的价格水平.于是,在该厂商实现长期均衡时,由PA P e d -=,得： 6=138138-A 解得 A=161此外,根据几何意义,在该厂商实现长期均衡时,线性主观需求d 曲线的斜率的绝对值可以表示为： B=Q P A -=115.0200138161=-于是,该垄断竞争厂商实现长期均衡时的线性主观需求函数为：P=A-BQ=161-0.115Q或者 Q=115.0161P 8.某家灯商的广告对其需求的影响为 P=88-2Q+2A对其成本的影响为C=3Q 2+8Q+A其中 A 为广告费用;1求无广告情况下,利润最大化时的产量、价格与利润2求有广告情况下,利润最大化时的产量、价格、广告费与利润 3比较1和2的结果解答：1若无广告,即A=0,则厂商的利润函数为πQ=P-CQ=88-2-3Q 2+8Q=88Q-2Q 2-3Q 2-8Q=80Q-5Q 2d πQ/dQ=80-10Q=0解得Q=8所以利润最大化时的产量Q=8P=88-2Q=88-28=72π=80Q-5Q 2=3202若有广告,即A>0,即厂商的利润函数为πQ,A=PQ,AQ-CQ,A=88-2Q+2A Q-3Q2+8Q+A=80Q-5Q2+2Q A-A分别对Q,A微分等于0得80-10Q+2A=0Q/A-1=0得出Q=A解得：Q=10,A=100代人需求函数和利润函数,有P=88-2Q+2A=88π=80Q-5Q2+2Q A-A=4003比较以上1与2的结果可知,此厂商在有广告的情况下,由于支出100的广告费,相应的价格水平由原先无广告时的72上升为88,相应的产量水平由无广告时的8上升为10,相应的利润也由原来无广告时的320增加为4009、用图说明垄断厂商短期和长期均衡的形成及其条件.解答：要点如下：1关于垄断厂商的短期均衡.垄断厂商在短期内是在给定的生产规模下,通过产量和价格的调整来实现MR=SMC的利润最大化原则.如图1-41所示书P83,垄断厂商根据MR=SMC的原则,将产量和价格分别调整到P0和Q0,在均衡产量Q0上,垄断厂商可以赢利即л>0,如分图a所示,此时AR>SAC,其最大的利润相当与图中的阴影部分面积；垄断厂商也可以亏损即л＜0,如分图b所示,此时,AR＜SAC,其最大的亏待量相当与图中的阴影部分.在亏损的场合,垄断厂商需要根据AR与AVC的比较,来决定是否继续生产：当AR>AVC时,垄断厂商则继续生产；当AR＜AVC时,垄断厂商必须停产；而当AR=AVC时,则垄断厂商处于生产与不生产的临界点.在分图b中,由于AR＜AVC,故该垄断厂商是停产的.由此,可得垄断厂商短期均衡的条件是： MR=SMC,其利润可以大于零,或小于零,或等于零.2关于垄断厂商的长期均衡.在长期,垄断厂商是根据MR=LMC的利润最大化原则来确定产量和价格的,而且,垄断厂商还通过选择最优的生产规模来生产长期均衡产量.所以,垄断厂商在长期可以获得比短期更大的利润.在图1-42中,在市场需求状况和厂商需求技术状况给定的条件下,先假定垄断厂商处于短期生产,尤其要注意的是,其生产规模是给定的,以SAC0曲线和SMC0所代表,于是,根据MR=SMC的短期利润最大化原则,垄断厂商将短期均衡产量和价格分别调整为Q0和P0,并由此获得短期润相当于图中较小的那块阴影部分的面积P0ABC.下面,再假定垄断厂商处于长期生产状态,则垄断厂商首先根据MR=LMC的长期利润最大化的原则确定长期的均衡产量和价格分别为Q和P,然后,垄断厂商调整全部生产要素的数量,选择最优的生产规模以SAC曲线和SMC曲线所表示,来生产长期均衡产量Q.由此,垄断厂商获得的长期利润相当于图中较大的阴影部分的面积PDE0F.显然,由于垄断厂商在长期可以选择最优的生产规模,而在短期只能在给定的生产规模下生产,所以,垄断厂商的长期利润总是大于短期利润.此外,在垄断市场上,即使是长期,也总是假定不可能有新厂商加入,因而垄断厂商可以保持其高额的垄断利润.由此可得,垄断厂商长期均衡的条件是：MR=LMC=SMC,且л>0.10、试述古诺模型的主要内容和结论.解答：要点如下：1在分析寡头市场的厂商行为的模型时,必须首先要掌握每一个模型的假设条件.古诺模型假设是：第一,两个寡头厂商都是对方行为的消极的追随者,也就是说,每一个厂商都是在对方确定了利润最大化的产量的前提下,再根据留给自己的的市场需求份额来决定自己的利润最大化的产量；第二,市场的需求曲线是线性的,而且两个厂商都准确地知道市场的需求状况；第三,两个厂商生产和销售相同的产品,且生产成本为零,于是,它们所追求的利润最大化目标也就成了追求收益最大化的目标.2在1中的假设条件下,古诺模型的分析所得的结论为：令市场容量或机会产量为Q O ,则每个寡头厂商的均衡产量为31Q O ,行业的均衡产量为32Q O ,.如果将以上的结论推广到m 个寡头厂商的场合,则每个寡头厂商的均衡产量为11+m Q O ,行业的均衡总产量为1+m m Q O . 3关于古诺模型的计算题中,关键要求很好西理解并运用每一个寡头厂商的反应函数：首先,从每个寡头厂商的各自追求自己利润最大化的行为模型中求出每个厂商的反映函数.所谓反应函数就是每一个厂商的的最优产量都是其他厂商的产量函数,即Q i=fQ j ,i 、j=1、2,i j ≠.然后,将所有厂商的反应函数联立成立一个方程组,并求解多个厂商的产量.最后所求出的多个厂商的产量就是古诺模型的均衡解,它一定满足2中关于古诺模型一般解的要求.在整个古诺模型的求解过程中,始终体现了该模型对于单个厂商的行为假设：每一个厂商都是以积极地以自己的产量去适应对方已确定的利润最大化的产量.11、弯折的需求曲线是如何解释寡头市场上的价格刚性现象的 解答：要点如下：1弯折的需求曲线模型主要是用来寡头市场上价格的刚性的.该模型的基本假设条件是：若行业中的一个寡头厂商提高价格,则其他的厂商都不会跟着提价,这便使得单独提价的厂商的销售量大幅度地减少；相反,若行业中的一个寡头厂商降低价格,则其他的厂商会将价格降到同一水平,这便使得首先单独降价的厂商的销售量的增加幅度是有限的.2由以上1的假设条件,便可以推导出单个寡头厂商弯折的需求曲线：在这条弯折的需求曲线上,对应于单个厂商的单独提价部分,是该厂商的主观的d需求曲线的一部分；对应于单个厂商首先降价而后其他厂商都降价的不分,则是该厂商的实际需求份额D曲线.于是,在d需求曲线和D需求曲线的交接处存在一个折点,这便形成了一条弯折的需求曲线.在折点以上的部分是d需求曲线,其较平坦即弹性较大；在折点以下的部分是D需求曲线,其较陡峭即弹性较小.3与2中的弯折的需求曲线相适应,便得到间断的边际收益MR曲线.换言之,在需求曲线的折点所对应的产量上,边际收益MR曲线是间断的,MR值存在一个在上限与下限之间的波动范围.4正是由于3,所以,在需求曲线的折点所对应的产量上,只要边际成本MC曲线的位置移动的范围在边际收益MR曲线的间断范围内,厂商始终可以实现MR=MC的利润最大化的目标.这也就是说,如果厂商在是生产过程中因技术、成本等因素导致边际成本MC发生变化,但只要这种变化使得MC曲线的波动不超出间断的边际收益MR曲线的上限与下限,那就始终可以在相同的产量和相同的价格水平上实现MR=MC的利润最大化原则.至此,弯折的需求曲线便解释了寡头市场上的价格刚性现象.。
曼昆《经济学原理(微观经济学分册)》(第6版)课后习题详解(第7章 消费者、生产者与市场效率)
曼昆《经济学原理（微观经济学分册）》（第6版）第3篇 市场和福利第7章 消费者、生产者与市场效率课后习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
一、概念题1．福利经济学（welfare economics ）答：福利经济学是一种规范经济学，研究的是整个经济的资源配置与个人福利的关系，特别是市场经济体系的资源配置与福利的关系，以及与此有关的各种政策问题。
福利经济学研究要素在不同厂商之间的最优分配以及产品在不同家庭之间的最优配置。
它的主要特点是：从一定的价值判断出发建立理论体系，在边际效用论的基础上建立福利概念，依据既定的社会目标和福利理论制定经济政策。
20世纪初，西方国家为调和日益尖锐的社会矛盾，福利经济学应运而生。
英国经济学家A ·C ·庇古是福利经济学的创始人和主要代表。
庇古1920年出版的《福利经济学》是福利经济学产生的标志。
庇古的福利经济学有两个基本命题：一是国民收入总量愈大，社会经济福利愈大；二是国民收入分配愈均等，社会经济福利愈大。
由于在1929～1933年的大危机以后，庇古的理论已经不能完全适应需要，因此他的理论被称为旧福利经济学。
与庇古的旧福利经济学相对的是其后出现的新福利经济学，代表人物有勒纳、卡尔多、希克斯等。
2．支付意愿（willingness to pay ）答：支付意愿指买者愿意为某种商品支付的最高价格。
支付意愿是衡量买者对物品的评价，评价越高支付意愿越强，愿意支付的价格越高，反之，评价越低支付意愿越弱，愿意支付的价格越低。
3．消费者剩余（consumer surplus ）（西北大学2004、2006研；华南理工大学2007、2008研；北京工业大学2008研）答：消费者剩余指消费者购买一定数量的某种产品时愿意支付的价格与其实际所支付的价格之间的差额。
1_7章答案_《经济学原理》习题集
《经济学原理》习题集第二章需求、供给与均衡价格一、单项选择题1、咖啡的价格急剧上升时，对茶叶的需求量将（B ）。
A．减少B．增加C．保持不变D．无法判断2、某商品价格下降导致其互补品的（B ）。
A．需求曲线向左移动B．需求曲线向右移动C．供给曲线向右移动D．价格上升3、在下列价格弹性的表述中，正确的是A(A) 需求量变动对价格变动的反应程度(B) 价格变动的绝对值对需求量变动的绝对值的影响(C) 价格的变动量除以需求的变动量(D) 需求的变动量除以价格的变动量4、当网球拍的价格下降时，消费者对网球的需求量A（不属于无弹性物品）(A) 增加(B) 减少(C) 不变(D) 变动情况不能确定5、在下列需求价格弹性的表达中，正确的是（A ）。
A．需求量变动对价格变动的反应程度B．价格变动的绝对值对需求量变动的绝对值的影响C．价格的变动量除以需求的变动量D．需求的变动量除以价格的变动量6、如果某种商品的需求富有弹性，则意味着价格一定程度的下跌将会导致（A ）。
A．卖者总收益增加B．买者需求量减少C．买者总支出减少D．买者需求量增加7、某商品的需求价格为98元，需求数量为200件，价格下降到80元，需求数量仍保持原来的水平，那么该种商品的需求价格弹性是（C ）A 1B 1.2C 0D 不能确定8、如果价格上升10%能使买者总支出增加2%，则该商品的需求价格弹性（A ）。
A．缺乏弹性B．富有弹性C．具有单位弹性D．完全无弹性9、低档商品的收入弹性为（C ）。
A．等于零B．大于零C．小于零D．大于110、某商品供给富有弹性，若该商品价格下降10％，则供给量B(A) 也下降10％(B) 下降幅度大于10％(C) 下降幅度小于10％(D) 不能确定11、某商品的收入弹性为一2，此商品可能是D(A) 高档化妆品(B) 小轿车(C) 移动电话(D) 白菜二、多项选择题1．均衡价格就是B CA ．供给量等于需求量时的价格B ．供给价格等于需求价格，同时供给量也等于需求量时的价格C ．供给曲线与需求曲线交点时的价格D ．供给等于需求时的价格E ．需求等于供给时的价格2．需求曲线是由下列哪些因素决定的A B CA ．边际效用最大化B ．消费者均衡的考虑C ．价格的高低D ．在既定收入情况下，实现效用最大化的考虑E ．政府意志3．以下关于需求价格弹性大小与销售收入的论述中，正确的是B EA ．需求弹性越大，销售收入越大B ．如果商品富有弹性，则降价可以扩大销售收入C ．如果商品缺乏弹性，则降价可以扩大销售收入D ．如果商品富有弹性，则降价可以提高利润E ．如果商品为单位弹性，则价格对销售收入没有影响4．根据需求弹性的弹性系数的大小，可以把需求的价格弹性分为A B C D EA ．富有弹性B ．缺乏弹性C ．单元弹性D ．无弹性E ．弹性无穷大三、计算题1、市场研究显示出以下有关巧克力棒市场的信息：需求表可以表示为方程式：QD=1600-300P ，这里QD 是需求量，P 是价格。
平狄克《微观经济学》(第7版)习题详解(第7章-生成成本)
平狄克《微观经济学》（第7版）第7章生产成本课后复习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
1．某公司支付给会计人员10000美元的年薪，这笔费用是一项经济成本吗？答：这笔费用是一项经济成本。
经济成本是显性成本和隐性成本之和。
显性成本指实际支出，所有涉及到货币交易行为的成本都属于显性成本。
隐性成本是一种经济成本，不涉及到货币交易行为，但涉及到生产中所使用的资源的成本。
当一个公司支付给会计人员10000美元年薪时，这是一笔货币交易，这笔费用是会计人员用劳动换来的收入。
因此，这笔费用属于经济成本中的显性成本。
2．某小零售店女店主自己做账，你将如何计算她工作的机会成本？答：该店主自己做账的机会成本是：她利用做账的时间和精力做其他事情时所能获得的最大收入。
根据机会成本的定义，如果该小零售店女店主不是自己做账，她可以在这段时间里做其他的事情，例如做小生意或者参加一些休闲活动。
那么，女店主自己做账的机会成本就是她用于做账的时间做其他事情时所能获得的最大收入。
3．解释以下说法正确与否：（1）如果一家企业的拥有者不给自己支付工资，则会计成本为零，而经济成本为正。
（2）会计利润为正的企业不一定经济利润也为正。
（3）企业雇佣了一些目前处于失业状态的工人，则其使用这些工人服务的机会成本为零。
答：（1）正确。
因为这里不存在货币交易，所以不存在会计成本（或显性成本）。
但是，因为企业的拥有者可以受雇于其他企业，因而存在经济成本。
经济成本为正，反映了此人工作时间的机会成本。
（2）正确。
会计利润仅考虑显性成本。
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第七章 消费者、生产者与市场效率复习题：1、解释买者的支付意愿、消费者剩余和需求曲线如何相关。
答：需求曲线反映了买者的支付意愿。
在任何一种数量时，需求曲线给出的价格表示边际买者的支付意愿。
需求曲线以下和价格以上的总面积是一种物品或劳务市场上所有买者消费者剩余的总和。
2、解释卖者的成本、生产者剩余和供给曲线如何相关。
答：供给曲线的高度与卖者的成本相关。
在任何一种数量时，供给曲线给出的价格表示边际卖者的成本。
供给曲线以上和价格以下的总面积衡量市场的生产者剩余。
3、在供求图中，说明市场均衡时的生产者和消费者剩余。
答：4、什么是效率？它是经济决策者的唯一目标吗？答：效率是指资源配置使社会所有成员得到的总剩余最大化的性质。
价格均衡价格数量 APE 的面积代表消费者剩余；PBE 的面积代表生产者剩余。
除了效率外，经济决策者还应该关心平等。
实际上，市场交易的好处很像在市场参与者之间分割一块蛋糕，经济决策者不仅要关心如何奖经济蛋糕做大，即效率；还要考虑如何在市场参与者之间分割这块蛋糕，这就涉及公平问题。
5、看不见的手有什么作用？答：每一个市场参与者都会尽力追求自己的利益，看不见的手指引他们在相互竞争中达到一个并非他们本意想要达到的目的，这就是市场均衡点。
在均衡点上，消费者剩余和生产者剩余总和最大化，整个社会福利达到最大。
6、说出两种市场失灵的名字。
解释为什么每一种都可能使市场结果无效率。
答：市场失灵包括市场势力和外部性。
如果某一市场上存在市场势力，即只有极少部分（可能是一个）买者或卖者可以控制的市场价格，他们就会使价格倾向于对他们这一小部分人有益的水平。
于是，市场价格和数量背离供求平衡，社会福利达不到最大，市场失去效率。
外部性是某些市场参与者的行为对旁观者福利的影响。
它使市场福利还要取决于买者评价和卖者成本之外的其他因素。
由于买者和卖者在决定消费和生产时并没有考虑这种负作用。
所有，从整个社会角度来看，市场均衡可能是无效率的。
问题与应用：1、加利福尼亚早来的寒流使柠檬变酸。
在柠檬市场上消费者剩余会有什么变动？在柠檬市场上消费者剩余会有什么变动？用图形说明你的答案。
答：柠檬变酸，消费者对柠檬的评价下降，需求曲线向左下方移动。
在其他条件不变的情况下，消费者剩余减少。
如A 图所示，柠檬质量下降，使需求曲线从D1下降到D2，APE 是原先的消费者剩余，A ’P ’E ’是变动后的消费者剩余，APE>A ’P ’E ’。
由于柠檬价格的下降，柠檬水的投入成本减少，柠檬水的价格也下降。
在其他条件不变的情况下，柠檬水市场上消费者剩余增加，如图B 所示。
2、假设法国面包的需求增加。
在法国面包市场上生产者剩余会发生什么变动？面粉市场上生产者剩余会发生什么变动？用图形说明你的答案。
答：价格数量 数量 A ．柠檬市场 B ．柠檬水市场OO由于需求增加，在其他条件不变的情况下，法国面包的价格会上升，市场上生产者剩余增加。
如图A ，价格从P1上升到P2，销售量从Q1上升到Q2，生产者剩余从面积P1BE1增加到P2BE2。
由于面包产量上升，它的生产要素面粉的需求量也会上升。
在其他条件不变的情况下，面粉的价格会上升，市场上生产者剩余增加。
如图B 所示，生产者剩余从面积P1BE1增加到P2BE2。
10、20世纪80年代末和90年代初加利福尼亚许多地方经历了严重的干旱。
A ．用水市场的图形说明干旱对水的均衡价格和数量的影响。
答：干旱使水的供给曲线S 向左上方移动到S ’。
水的均衡价格从P0上升到P1，均衡数量从Q0下降到Q1。
数量 数量A ．面包市场的生产者剩余B ．面粉市场的生产者剩余Q2 Q2 Q1 Q1B ．但是，许多社区不允许水价变动。
这种政策对水市场有什么影响？用你的图说明会出现短缺还是过剩。
答：这种政策使水市场发生了短缺。
水的供给量Q2小于水的需求量Q3，如下图。
C ．1991年《华尔街日报》上的读者来信指出，“要求所有洛杉矶居民在他们1986年用水水平的基础上从3月1日起减少10%的用水，价格数量限定的水价需求量 Q3 均衡量 Q1供给量Q2 价格数量干旱时的价格干旱前的价格干旱前的均衡量Q0 干旱时的均衡量Q1 干旱时的均衡价格从5月1日起再减少10%。
”作者根据效率和平等原则批评这种政策，他说：“这种政策不仅奖励那些在1986年‘浪费’水更多的家庭，很少能鼓励那些还能再减少用水的消费者，（而且）……惩罚了那些无法立即减少用水的消费者。
”洛杉矶这种制度在哪一方面使水的配置无效率？又在哪一方面看来不公平？答：这种制度没有把水卖给对它评价最高的人。
要求每个消费者都同比例减少自己的用水量，那些平时用水很浪费的人减少这个比例的用水对他的效用不会有多少影响。
但那些平时就很节水的人减少这个比例的用水，会使他们的消费者剩余大大减少，因为他们对水的评价比浪费水的人高，但市场又不能满足他们的交易要求。
另外，这种制度没有给人们一种主动节水的激励，人们只要将用水量减少规定的比例就没有理由再减少更多的用水量。
所以，这种制度使水的配置无效率。
这种制度对平时节水的消费者不公平。
因为他们每节约1单位水的成本要大于平时浪费水的消费者，但他们又和平时浪费水的消费者被规定了相同的节水比例。
D．假设洛杉矶改为允许水价一直上升到需求量等于供给量。
这会使水的配置较有效率吗？按你的观点，这种做法比报纸文章中提到的同比例减少用水公平呢，还是不公平？什么方法能使市场解决方法更公平？答：允许水价一直上升到需求量等于供给量，这会使水的配置较有效率。
市场是最有效率的资源配置手段。
这种做法与报纸文章中提到的同比例减少用水存在一样的问题，是不公平的。
水价上升，平时浪费水的消费者可以比平时节水的消费者更容易减少用水量，从而减少水费支出。
可以采取适当的补贴使市场解决方法更公平。
第八章应用：税收的代价复习题：1、当对一种物品征税时，消费者和生产者剩余会发生什么变动？如何把消费者和生产者剩余变动与税收收入进行比较？解释原因。
答：当对一种物品征税时，消费者和生产者剩余都会减少。
我们可以用税收前后的总福利来比较消费者剩余和生产者剩余变动与税收收入，看税收前的福利与税收后的福利谁大谁小。
税收前的福利=生产者剩余+消费者剩余，税收后的福利=生产者剩余+消费者剩余+税收收入。
税收前的福利大于税收后的福利，说明消费者剩余和生产者剩余的减少大于税收收入。
反之，则小于。
2、画出有物品销售税的供求图。
说明无谓损失。
说明税收收入。
答：如下图所示，对一种征税减少了消费者剩余（面积B+E表示减少量）和生产者剩余（面积C+F表示减少量）。
生产者和消费者剩余的减少大于税收收入（用面积B+C表示），税收引起了无谓损失（用面积E+F表示）。
3、供给与需求弹性如何影响税收的无谓损失？为什么有这种影响？ 答：供给与需求曲线的弹性越大，税收的无谓损失越大；供给与需求曲线曲线的弹性越小，税收的无谓损失越小。
因为供给与需求弹性衡量买者和卖者对价格变动的反应程度，决定了税收扭曲会使市场结果有多大变动。
4、为什么专家对劳动税无谓损失大还是小的看法不一致？答：专家对劳动税无谓损失大还是小的看法不一致，部分是由于他们对供给和需求的价格弹性大小的看法不一致。
在任何一个市场上，供给和需求越富有弹性，该市场上的税收对行为的扭曲就越大，而劳动力市场的供给和需求的价格弹性大小是在改变的。
5、当税收增加时，无谓损失和税收收入有什么变动？答：当税收增加时，无谓损失增加，并且无谓损失的增加要快于税收规模的增加。
税收增加时，税收收入先增加，然后随着税收规模越来越大，市场收缩非常之大，以至于税收收入开始减少。
价格数量Q2 Q1 买者支付的价格没有税收时的价格卖者得到的的价格问题与应用：1、批萨饼市场的特征是向右下方倾斜的需求曲线和向右上方倾斜的供给曲线。
A ．画出竞争市场均衡图。
标出价格、数量、消费者剩余和生产者剩余。
有无谓损失吗？解释原因。
答：B ．假设政府强迫每个批萨饼店每卖出一个批萨饼缴纳1元税。
说明这种批萨饼税的影响，确定并标出消费者剩余、生产者剩余、政府收入以及无谓损失。
如何把每块面积与税前的情况相比较？答：这种披萨饼税使卖者得到的价格降低，买者支付的价格上升，销售量从Q1减少到Q2。
消费者剩余由税收前的面积A+B+E 减少到税收后的面积D 。
税收收入为面积B+C 。
无谓损失为面积E+F 。
税收前没有税收收入和无谓损失（见下图）。
数量O 价格均衡价格P没有无谓损失。
自由竞争市场使供给与需求达到均衡点，消费者对该物品的评价等于生产者的成本。
在均衡状态下，总剩余达到最大，如左图。
C ．如果取消税收，批萨饼的消费者和卖者的状况在变好，但政府会失去税收收入。
假设消费者和生产者自愿把他们的部分收入给予政府。
各方的状况能比有税收时变好吗？用你的图上所标出的面积作出解释。
答：如果取消税收，消费者和生产者自愿把收入交给政府，他们对市场的需求和供给就不会改变，市场仍处于原有的均衡状态。
虽然买者实际支付的价格上升了，卖者实际得到的价格下降了，但销售了不变。
买者和卖者所得减少的部分都交给了政府，不存在无谓损失。
各方的状况必有税收的时好。
如上图所示，如果披萨饼的生产者交给政府的收入是C ，消费者交的是B ，此时消费量仍是Q1，生产者剩余是面积D+F ，消费者剩余是A+E ，没有无谓损失。
10、大多数州对购买新汽车征税。
假定现在新泽西州要求汽车中间商每卖一辆汽车向州政府叫100元税，并计划在下一年把每辆汽车的税增加到150元。
价格数量Q2 Q1 买者支付的价格没有税收时的价格卖者得到的的价格A．说明这种税收增加对新泽西汽车销售量、消费者支付的价格和生产者得到的价格的影响。
答：这种税收增加对新泽西汽车销售量下降，消费者支付的价格上升，生产者得到的价格下降。
B．做一个表，表示税收增加前后的消费者剩余、生产者剩余、政府收入和总剩余的水平。
答：C．政府收入有什么变动？是正的还是负的？答：政府收入变动，是正是负还需要考察这种税收规模使新泽西州的汽车市场处在拉伐曲线的哪一边。
如果150元/辆的税使市场处在拉伐曲线不利的一边，则政府收入变动为负；如果150元/辆的税收下，市场仍处在拉伐曲线有利的一边，则政府收入变动为正。
D．无谓损失有什么变动？是正的还是负的？答：无谓损失增加。
税收增加会使市场规模进一步减小，产生更大的无谓损失。
E．给出一个理由，说明为什么新泽西州的汽车需求是相当富有弹性的。
这种汽车需求富有弹性使额外的税收增加还是减少了政府收入？该州应该如何努力减少需求弹性？答：假设新泽西因为收入水平较低，使汽车需求相对富有弹性。
在这种情况下，价格上升就会有许多人退出市场，市场规模随税收的增加而收缩的很快，无谓损失太大，税收收入负增长。