微观经济ch14
曼昆微观经济学答案ch14
Firms in Competitive MarketsWHAT’S NEW IN THE THIRD EDITION:There have been no substantial changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:what characteristics make a market competitive.how competitive firms decide how much output to produce.how competitive firms decide when to shut down production temporarily.how competitive firms decide whether to exit or enter a market.how firm behavior determines a market’s short -run and long-run supply curves.CONTEXT AND PURPOSE:Chapter 14 is the second chapter in a five-chapter sequence dealing with firm behavior and theorganization of industry. Chapter 13 developed the cost curves on which firm behavior is based. These cost curves are employed in Chapter 14 to show how a competitive firm responds to changes in market conditions. Chapters 15 through 17 will employ these cost curves to see how firms with market power (monopolistic, oligopolistic, and monopolistically competitive firms) respond to changes in market conditions. The purpose of Chapter 14 is to examine the behavior of competitive firms —firms that do not have market power. The cost curves developed in the previous chapter shed light on the decisions that lie behind the supply curve in a competitive market.FIRMS IN COMPETITIVEMARKETS14264 Chapter 14/Firms in Competitive MarketsKEY POINTS:1.Because a competitive firm is a price taker, its revenue is proportional to the amount of output itproduces. The price of the good equals both the firm’s average revenue and its marginal rev enue.2.To maximize profit, a firm chooses a quantity of output such that marginal revenue equals marginalcost. Because marginal revenue for a competitive firm equals the market price, the firm chooses quantity so that price equals marginal cost. Thus, t he firm’s marginal cost curve is its supply curve.3.In the short run when a firm cannot recover its fixed costs, the firm will choose to shut downtemporarily if the price of the good is less than average variable cost. In the long run when the firm can recover both fixed and variable costs, it will choose to exit if the price is less than average total cost.4.In a market with free entry and exit, profits are driven to zero in the long run. In this long-runequilibrium, all firms produce at the efficient scale, price equals minimum average total cost, and the number of firms adjusts to satisfy the quantity demanded at this price.5.Changes in demand have different effects over different time horizons. In the short run, an increasein demand raises prices and leads to profits, and a decrease in demand lowers prices and leads to losses. But if firms can freely enter and exit the market, then in the long run the number of firms adjusts to drive the market back to the zero-profit equilibrium.CHAPTER OUTLINE:I. What Is a Competitive Market?A. The Meaning of Competition1. Definition of competitive market: a market with many buyers and sellerstrading identical products so that each buyer and seller is a price taker.2. There are three characteristics of a competitive market (sometimes called aperfectly competitive market).a. There are many buyers and sellers.b. The goods offered by the sellers are largely the same.c. Firms can freely enter or exit the market.Chapter 14/Firms in Competitive Markets 265B. The Revenue of a Competitive Firm1. Total revenue from the sale of output is equal to price times quantity.2. Definition of average revenue: total revenue divided by the quantity sold.3. Definition of marginal revenue: the change in total revenue from anadditional unit sold.II. Profit Maximization and the Competitive Firm's Supply CurveA. A Simple Example of Profit Maximization: The Smith Dairy Farm266 Chapter 14/Firms in Competitive Markets1.In this example, profit is maximized if the farm produces 4 or 5 gallons of milk (see the fourth column).2.The profit-maximizing quantity can also be found by comparing marginal revenue and marginal cost. a. As long as marginal revenue exceeds marginal cost, increasing output will raise profit.b.If marginal revenue is less than marginal cost, the firm can increase profit by decreasing output.c.Profit-maximization occurs where marginal revenue is equal to marginal cost.B. The Marginal-Cost Curve and the Firm's Supply DecisionChapter 14/Firms in Competitive Markets 2671.Cost curves have special features that are important for our analysis. a. The marginal-cost curve is upward sloping. b. The average-total-cost curve is u-shaped.c.The marginal-cost curve crosses the average-total-cost curve at the minimum of average total cost.2. Marginal and average revenue can be shown by a horizontal line at the market price.3. To find the profit-maximizing level of output, we can follow the same rules that we discussed above.a.If marginal revenue is greater than the marginal cost, the firm can increase its profit by increasing output.b. If marginal cost is greater than marginal revenue, the firm can increase its profit by decreasing output.c. At the profit-maximizing level of output, marginal revenue is equal to marginal cost.268 Chapter 14/Firms in Competitive MarketsChapter 14/Firms in Competitive Markets 2694. If the price in the market were to change to P2, the firm would set its new levelof output by equating marginal revenue and marginal cost.5. Because the firm's marginal cost curve determines how much the firm is willingto supply at any price, it is the competitive firm's supply curve.C. The Firm's Short-Run Decision to Shut Down1. In some circumstances, a firm will decide to shut down and produce zero output.2. There is a difference between a temporary shutdown of a firm and an exit fromthe market.a. A shutdown refers to the short-run decision not to produce anythingduring a specified period of time because of current market conditions.b. Exit refers to a long-run decision to leave the market.c. One important difference is that, when a firm shuts down temporarily, itstill must pay fixed costs.3. If a firm shuts down, it will earn no revenue and will have only fixed costs (novariable costs).4. Therefore, a firm will shut down if the revenue that it would get from producingis less than its variable costs of production:Shut down if TR < VC.270 Chapter 14/Firms in Competitive Markets5.Since TR = P H Q and VC = AVC H Q , we can rewrite this condition as: Shut down if P < AVC .6.We now can tell exactly what the firm will do to maximize profit (or minimize loss).a.If the price is less than average variable cost, the firm will produce no output.b. If the price is above average variable cost, the firm will produce the level of output where marginal revenue (price) is equal to marginal cost.7.Therefore, the competitive firm's short-run supply curve is the portion of its marginal revenue curve that lies above average variable cost.8.Spilt Milk and Sunk Costs a. Definition of sunk cost: a cost that has been committed and cannot be recovered .b. Once a cost is sunk, it is no longer an opportunity cost.c.Because nothing can be done about sunk costs, you should ignore them when making decisions.Chapter 14/Firms in Competitive Markets 2719. Case Study: Near-Empty Restaurants and Off-Season Miniature Golfa. In making a decision of whether or not to open for lunch, a restaurantowner must weigh revenue with variable costs. (Much of the cost ofrunning a restaurant is somewhat fixed.)b. The same criteria would apply to a decision of whether a miniature golfcourse in a summer resort community should stay open during otherseasons. The course should only be open if revenue exceeds variablecosts.D. The Firm's Long-Run Decision to Exit or Enter a Market1. If a firm exits the market, it will earn no revenue, but it will have no costs as well.2. Therefore, a firm will exit if the revenue that it would earn from producing is lessthan its total costs:Exit if TR < TC.3. Since TR = P H Q and TC = ATC H Q, we can rewrite this condition as:Exit if P < ATC.4. A firm will enter an industry when there is profit potential, so this must meanthat a firm will enter if revenues will exceed costs:Enter if P > ATC.272 Chapter 14/Firms in Competitive Markets5.Because, in the long run, a firm will remain in a market only if P ≥ ATC , the firm's long-run supply curve will be its marginal cost curve above ATC .E.Measuring Profit in Our Graph for the Competitive Firm 1. Recall that Profit = TR - TC .2.Because TR = P H Q and TC = ATC H Q , we can rewrite this equation: Profit = (P – ATC ) H Q .3. Using this equation, we can measure the amount of profit (or loss) at the firm's profit-maximizing level of output (or loss-minimizing level of output).III. The Supply Curve in a Competitive Market A.The Short Run: Market Supply with a Fixed Number of Firms1. Example: a market with 1,000 identical firms.2. Each firm's short-run supply curve is its marginal cost curve above average variable cost.3.To get the market supply curve, we add the quantity supplied by each firm in the market at every given price.B. The Long Run: Market Supply with Entry and Exit 1. If firms in an industry are earning profit, this will attract new firms.a. The supply of the product will increase (the supply curve will shift to theright).b.The price of the product will fall and profit will decline.2.If firms in an industry are incurring losses, firms will exit.a. The supply of the product will decrease (the supply curve will shift to theleft).b. The price of the product will rise and losses will decline.3. At the end of this process of entry or exit, firms that remain in the market mustbe making zero economic profit.4. Because Profit = TR–TC, profit will only be zero when:TR = TC.5. Because TR = P H Q and TC = ATC H Q, we can rewrite this as:P = ATC.6. Therefore, the process of entry or exit ends only when price and average totalcost become equal.7. This implies that the long-run equilibrium of a competitive market must havefirms operating at their efficient scale.8. Why Do Competitive Firms Stay in Business If They Make Zero Profit?a. Profit is equal to total revenue minus total cost.b. To an economist, total cost includes all of the opportunity costs of thefirm.c. When a firm is earning zero profit, this must mean that the firm'srevenues are compensating the firm's owners for the time and moneythat they have expended to keep their businesses going.C. A Shift in Demand in the Short Run and Long Run1. Assume that the market begins in long-run equilibrium. This means that firmsare earning zero profit and price equals the minimum of average total cost.2. If the demand for the product increases, this will lead to an increase in the priceof the good.3. Firms will respond to the increase in price by producing more in the short run.4. Because price is now greater than average total cost, firms are earning profit.5. The profit will attract new firms into the industry, shifting the supply curve to theright.6. This will lower price until it falls back to the minimum of average total cost andfirms are once again earning zero economic profit.7. In the News: Entry or Overinvestment?a. Strong demand leads to high prices, high profits and then eventuallyentry of new firms.b. This is an article from The Wall Street Journal discussing how businessleaders often see entry (and therefore reduced profits) as―overinvestment.‖D. Why the Long-Run Supply Curve Might Slope Upward1. Because we assumed that all potential entrants faced the same costs as existingfirms, average total cost of each firm was unaffected by the entry of new firmsinto the industry.2. In this situation, the long-run supply of the industry will be a horizontal line atminimum average total cost.3. However, there are two possible reasons why this may not be the case.a. If a resource is limited in quantity, entry of firms will increase the priceof this resource, raising the average total cost of production.b. If firms have different costs, then it is likely that those with the lowestcosts will enter the industry first. If the demand for the product thenincreases, the firms that would enter will likely have higher costs thanthose firms already in the market.4. In this situation, the long-run supply curve of the industry will be upward sloping.5. In either case, the long-run supply curve of an industry is generally more elasticthan the short-run supply curve of the industry (due to the fact that firms canenter or exit in the long run).SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. When a competitive firm doubles the amount it sells, the price remains the same, so its totalrevenue doubles.2. The price faced by a profit-maximizing firm is equal to its marginal cost because if price wereabove marginal cost, the firm could increase profits by increasing output, while if price werebelow marginal cost, the firm could increase profits by decreasing output.A profit-maximizing firm decides to shut down in the short run when price is less than averagevariable cost. In the long run, a firm will exit a market when price is less than average total cost.3. In the long run, with free entry and ex it, the price in the market is equal to both a firm’s marginalcost and its average total cost, as Figure 1 shows. The firm chooses its quantity so that marginal cost equals price; doing so ensures that the firm is maximizing its profit. In the long run, entryinto and exit from the industry drive the price of the good to the minimum point on the average-total-cost curve.Figure 1Questions for Review1. A competitive firm is a firm in a market in which: (1) there are many buyers and many sellers inthe market; (2) the goods offered by the various sellers are largely the same; and (3) usuallyfirms can freely enter or exit the market.2. Figure 2 shows the cost curves for a typical firm. For a given price (such as P*), the level ofoutput that maximizes profit is the output where marginal cost equals price (Q*), as long as price is greater than average variable cost at that point (in the short run), or greater than averagetotal cost (in the long run).Figure 23. A firm will shut down temporarily if the revenue it would get from producing is less than thevariable costs of production. This occurs if price is less than average variable cost.4. A firm will exit a market if the revenue it would get if it stayed in business is less than its totalcost. This occurs if price is less than average total cost.5. A firm's price equals marginal cost in both the short run and the long run. In both the short runand the long run, price equals marginal revenue. The firm should increase output as long asmarginal revenue exceeds marginal cost, and reduce output if marginal revenue is less thanmarginal cost. Profits are maximized when marginal revenue equals marginal cost.6. The firm's price equals the minimum of average total cost only in the long run. In the short run,price may be greater than average total cost, in which case the firm is making profits, or pricemay be less than average total cost, in which case the firm is making losses. But the situation is different in the long run. If firms are making profits, other firms will enter the industry, whichwill lower the price of the good. If firms are making losses, they will exit the industry, which will raise the price of the good. Entry or exit continues until firms are making neither profits norlosses. At that point, price equals average total cost.7. Market supply curves are typically more elastic in the long run than in the short run. In acompetitive market, since entry or exit occurs until price equals the minimum of average totalcost, the supply curve is perfectly elastic in the long run.Problems and Applications1. A competitive market is one in which: (1) there are many buyers and many sellers in the market;(2) the goods offered by the various sellers are largely the same; and (3) usually firms can freelyenter or exit the market. Of these goods, bottled water is probably the closest to a competitive market. Tap water is a natural monopoly because there's only one seller. Cola and beer are not perfectly competitive because every brand is slightly different.2. Since a new customer is offering to pay $300 for one dose, marginal revenue between 200 and201 doses is $300. So we must find out if marginal cost is greater than or less than $300. To do this, calculate total cost for 200 doses and 201 doses, and calculate the increase in total cost.Multiplying quantity by average total cost, we find that total cost rises from $40,000 to $40,401, so marginal cost is $401. So your roommate should not make the additional dose.3. a. Remembering that price equals marginal cost when firms are maximizing profit, we knowthe marginal cost must be 30 cents, since that is the price.b. The industry is not in long-run equilibrium since price exceeds average total cost.4. Once you have ordered the dinner, its cost is sunk, so it does not represent an opportunity cost.As a result, the cost of the dinner should not influence your decision about stuffing yourself.5. Since Bob’s average total cost is $280/10 = $28, which is greate r than the price, he will exit theindustry in the long run. Since fixed cost is $30, average variable cost is ($280 - $30)/10 = $25, which is less than price, so Bob won’t shut down in the short run.6. Here’s the table showing costs, revenues, an d profits:a. The firm should produce 5 or 6 units to maximize profit.b. Marginal revenue and marginal cost are graphed in Figure 3. The curves cross at aquantity between 5 and 6 units, yielding the same answer as in part (a).c. This industry is competitive since marginal revenue is the same for each quantity. Theindustry is not in long-run equilibrium, since profit is positive.Figure 37. a. Figure 4 shows the short-run effect of declining demand for beef. The shift of theindustry demand curve from D1 to D2 reduces the quantity from Q1 to Q2 and reduces theprice from P1 to P2. This affects the firm, reducing its quantity from q1 to q2. Before thedecline in the price, the firm was making zero profits; afterwards, profits are negative, asaverage total cost exceeds price.Figure 4b. Figure 5 shows the long-run effect of declining demand for beef. Since firms were losingmoney in the short run, some firms leave the industry. This shifts the supply curve fromS1 to S3. The shift of the supply curve is just enough to increase the price back to itsoriginal level, P1. As a result, industry output falls still further, to Q3. For firms thatremain in the industry, the rise in the price to P1 returns them to their original situation,producing quantity q1 and earning zero profits.Figure 58. Figure 6 shows that although high prices cause an industry to expand, entry into the industryeventually returns prices to the point of minimum average total cost. In the figure, the industry is originally in long-run equilibrium. The industry produces output Q1, where supply curve S1intersects demand curve D1, and the price is P1. At this point the typical firm produces output q1.Since price equals average total cost at that point, the firm makes zero economic profit.Now suppose an increase in demand occurs, with the demand curve shifting to D2. This causes"high prices" in the industry, as the price rises to P2. It also causes the industry to increaseoutput to Q2. With the higher price, the typical firm increases its output from q1 to q2, and now makes positive profits, since price exceeds average total cost.However, the positive profits that firms earn encourage other firms to enter the industry. Their entry, "an expansion in an industry," leads the supply curve to shift to S3. The new equilibrium reduces the price back to P1, "bringing an end to high prices and manufacturers' prosperity,"since now firms produce q1 and earn zero profit again. The only long-lasting effect is thatindustry output is Q3, a higher level than originally.Figure 69. a. Figure 7 shows the typical firm in the industry, with average total cost ATC1, marginalcost MC1, and price P1.b. The new process reduces Hi-Tech’s marginal cost to MC2 and its average total cost toATC2, but the price remains at P1 since other firms cannot use the new process. Thus Hi-Tech earns positive profits.c. When the patent expires and other firms are free to use the technology, all firms’average-total-cost curves decline to ATC2, so the market price falls to P3 and firms earnno profits.Figure 710. The rise in the price of petroleum increases production costs for individual firms and thus shiftsthe industry supply curve up, as shown in Figure 8. The typical firm's initial marginal-cost curve is MC1 and its average-total-cost curve is ATC1. In the initial equilibrium, the industry supplycurve, S1, intersects the demand curve at price P1, which is equal to the minimum average total cost of the typical firm. Thus the typical firm earns no economic profit.The increase in the price of oil shifts the typical firm's cost curves up to MC2 and ATC2, and shifts the industry supply curve up to S2. The equilibrium price rises from P1 to P2, but the price does not increase by as much as the increase in marginal cost for the firm. As a result, price is lessthan average total cost for the firm, so profits are negative.In the long run, the negative profits lead some firms to exit the industry. As they do so, theindustry-supply curve shifts to the left. This continues until the price rises to equal the minimum point on the firm's average-total-cost curve. The long-run equilibrium occurs with supply curve S3, equilibrium price P3, industry output Q3, and firm's output q3. Thus, in the long run, profitsare zero again and there are fewer firms in the industry.Chapter 14/Firms in Competitive Markets 283Figure 811. a. Figure 9 illustrates the situation in the U.S. textile industry. With no international trade,the market is in long-run equilibrium. Supply intersects demand at quantity Q1 and price$30, with a typical firm producing output q1.Figure 9b. The effect of imports at $25 is that the market supply curve follows the old supply curveup to a price of $25, then becomes horizontal at that price. As a result, demand exceedsdomestic supply, so the country imports textiles from other countries. The typicaldomestic firm now reduces its output from q1 to q2, incurring losses, since the large fixedcosts imply that average total cost will be much higher than the price.c. In the long run, domestic firms will be unable to compete with foreign firms becausetheir costs are too high. All the domestic firms will exit the industry and other countrieswill supply enough to satisfy the entire domestic demand.12. a. Figure 10 shows the current equilibrium in the market for pretzels. The supply curve, S1,284 Chapter 14/Firms in Competitive Marketsintersects the demand curve at price P1. Each stand produces quantity q1 of pretzels, sothe total number of pretzels produced is 1,000 x q1. Stands earn zero profit, since priceequals average total cost.b. If the city government restricts the number of pretzel stands to 800, the industry-supplycurve shifts to S2. The market price rises to P2, and individual firms produce output q2.Industry output is now 800 x q2. Now the price exceeds average total cost, so each firmis making a positive profit. Without restrictions on the market, this would induce otherfirms to enter the market, but they cannot, since the government has limited the numberof licenses.c. The city could charge a license fee for the licenses. Since it is a lump-sum fee for thelicense, not based on the quantity of sales, such a tax has no effect on marginal cost, sowon't affect the firm's output. It will, however, reduce the firm's profits. As long as thefirm is left with a zero or positive profit, it will continue to operate. So the license fee thatbrings the most money to the city is to charge each firm the amount (P2 - ATC2)q2, theamount of the firm's profit.Figure 1013. a. Figure 11 illustrates the gold market (industry) and a representative gold mine (firm).The demand curve, D1, intersects the supply curve at industry quantity Q1 and price P1.Since the industry is in long-run equilibrium, the price equals the minimum point on therepresentative firm's average total cost curve, so the firm produces output q1 and makeszero profit.b. The increase in jewelry demand leads to an increase in the demand for gold, shifting thedemand curve to D2. In the short run, the price rises to P2, industry output rises to Q2,and the representative firm's output rises to q2. Since price now exceeds average totalcost, the representative firm now earns positive profits.c. Since gold mines are earning positive economic profits, over time other firms will enterthe industry. This will shift the supply curve to the right, reducing the price below P2.But it's unlikely that the price will fall all the way back to P1, since gold is in short supply.Costs for new firms are likely to be higher than for older firms, since they'll have todiscover new gold sources. So it's likely that the long-run supply curve in the goldChapter 14/Firms in Competitive Markets 285 industry is upward sloping. That means the long-run equilibrium price will be higher thanit was initially.Figure 1114. a. Figure 12 shows cost curves for a California refiner and a non-California refiner. Sincethe California refiner has access to lower-cost oil, its costs are lower.Figure 12b. In long-run equilibrium, the price is determined by the costs of non-California refiners,since California refiners cannot supply the entire market. The market price will equal theminimum average total cost of the other refiners; they will thus earn zero profits. SinceCalifornia refiners have lower costs, they will earn positive profits, equal to (P* - ATC C) xQ C.c. Yes, there is a subsidy to California refiners that is not passed on to consumers. Thesubsidy accounts for the long-run profits of the California refiners. It arises simplybecause the oil cannot be exported.。
微观经济学(高鸿业版)知识点总结
微观经济学西方经济学的概念经济学是研究人们如何合理使用相对稀缺的资源来满足无限多样的需要的一门社会科学。
要生产更多的物品和劳务，从而需要更多的资源但在一定时期内可用于生产的资源与人们的需要相比总是远远不够的这就是资源的稀缺性经济学所研究的就是如何对有限的资源进行合理的配置以最大程度的满足人们需要的。
西方经济学产生的时期早，其发展经历了以下一个阶段：重商主义（产生于15世纪末期）--古典经济学（产生于17世纪中期，代表人物为威廉·配弟、亚当·斯密、李嘉图等）--古典经济学的庸俗化（产生于19世纪30年代，代表人物为萨伊、马尔萨斯）--边际效用经济学（产生于19世纪70年代，代表人物为门格尔、杰文斯、瓦尔拉斯）--新古典经济学（产生于19世纪末期，代表人物为马歇尔）--凯恩斯经济学（产生于20世纪30年代）--后凯恩斯主流经济学（产生于20世纪中期，代表人物为库兹涅茨、汉森、萨缪尔森、托宾、哈罗德等）--新自由主义经济学（产生于20世纪60年代，由货币学派、供给学派、理性预期学派、新制度经济学、公共选择学派、新左派和新自由主义学派组成）作为考察对象的科学。
它采用的个量分析的方法，研究的问题主要有：个人或家庭作为消费者如何把有限的收入分配于各种商品的消费上，以获得最大效用；单个生产者如何把有限的生产性资源分配于各种商品的生产上，以获得最大利润；商品市场和要素市场上均衡价格和均衡产量是如何决定的，等等微观经济学的核心是价格问题。
宏观经济学是把一个社会作为一个整体的经济活动作为考察对象，采用总量分析法，以国民收入为中心，以全社会福利为目标，从总供求的角度研究产品市场、货币市场、国际收支等方面的协调发展，以及怎样通过宏观调控达到资源的充分利用它研究的是诸如社会就业量、物价水平、经济增长、经济周期等全局性的问题微观经济学是宏观经济学的基础，如果形象化地把宏观经济学看作研究森林的特征，微观经济学则是考察构成森林的树木微观经济学的理论基础是以马歇尔为代表的新古典经济学，其核心是市场有效性和自由放任；宏观经济学的理论基础是凯恩斯主义经济学，其核心是市场失效和国家干预均衡是来自于物理学中的一个概念，它分析的是经济力量达到均衡所需要的条件以及均衡达到时会出现的情况，用数学语言来说就是所研究的经济问题中涉及各种变量，假定自变量为已知或不变，考察因变量达到均衡时所需要的条件和会出现的情况均衡分析有局部均衡和一般均衡之分。
中级微观经济学课件-Chapter14消费者剩余x
14.8 补偿变化和等价变化
– 补偿变化 – 等价变化
补偿变化
• 在价格变化后，要使消费者的境况同他在价格 变化以前的境况一样好，必须给他的货币数额。
• 就图形而论，新的预算线必须上移多少才能同 经过初始消费点的无差异曲线相切，使消费者 回复到他初始无差异曲线上所必须的收入变化 即收入的补偿变化。
的消费的支付意愿的总额。即消费n单位离散商 品x的效用，恰好就是组成需求函数的前n个长条
保留价格的和正好是消费商品X的总效用。 也是对该商品的消费的支付意愿的总额。
p
• 这块面积，即需求曲线以 下的面积，被称作商品X总 效用。或消费者总剩余或 总福利。
QD
• 消费的最终效用取决于消费者对x和y两种 商品的消费数量。如果消费者选择了n单位 离散商品x，他就会用剩余的m-pn元去购买 y,此时，他的总效用为：
4
保留价格的图像呈“阶梯”
3
形，这就是离散商品的需求
123
曲，rn ≥ p ≥ rn+1。由保留 价格可以构造出需QD求函数。
14.2 根据需求曲线构造效用函数
• 保留价格被定义为效用的差额，即 • r1=u（1）-u（0）， • r2=u（2）-u（1）， • r3=u（3）-u（2）， • 那么r1+r2+r3= u（3） -u（0）， • 假设u（0）=0 u（3） = r1+r2+r3 • r1+r2+……＋rn=u(n)-u(0)＝u(n) • u（n）就是前n个保留价格的和。也是对该商品
• (a) 小青有何种效用函数形式？ • (b) 写出他对商品X的反需求函数。
• (c) 假设小青收入为4,000元，商品X的价 格是50元，商品X的总效用是多少？净消 费者剩余是多少？商品X和商品Y的总效用 是多少？
微观经济学与宏观经济学
财政政策和货币政策的变化会对经济增长产生影响，通过 分析这些政策的变化，可以预测未来经济增长的趋势。
评估政策组合效果
财政政策和货币政策往往需要相互配合，通过分析政策组 合的实施效果，可以评估政策的有效性并为政策调整提供 依据。
06
微观经济学与宏观经济学的互动关系
微观经济学对宏观经济学的补充和完善
评估货币政策效果
货币政策通过调节货币供给来影响市场利率和通货膨胀，通过分析 货币供给与需求的变化，可以评估货币政策的实施效果。
财政政策与货币政策在微观经济分析中的应用
分析政策对总需求的影响
财政政策（如政府支出和税收）和货币政策（如利率和货 币供应）是影响总需求的重要因素，通过分析这些政策的 变化，可以了解总需求的变动情况。
国民收入核算数据可以为政府制定和调整经济政 策提供重要依据，同时也可用于评估政策实施效 果。
货币供给与需求在微观经济分析中的应用
分析市场均衡
货币供给与需求是决定市场利率的关键因素，通过分析货币市场 的均衡状态，可以了解市场利率的变动趋势。
预测通货膨胀
货币供给过多可能导致通货膨胀，通过分析货币供给与需求的变化 ，可以预测未来通货膨胀的趋势。
市场结构理论在宏观经济分析中的应用
市场结构与经济增长
市场结构与产业政策
市场失灵与政府干预
不同的市场结构对经济增长的影响不 同。完全竞争市场有利于资源的优化 配置和技术创新，而垄断市场则可能 导致资源配置的低效率和阻碍技术创 新。在宏观经济分析中，了解市场结 构的特点有助于评估经济增长的潜力 和质量。
生产者技术创新与产业升级
生产者的技术创新是推动产业升级和经济增长的重要因素 。在宏观经济分析中，关注生产者的技术创新活动有助于 预测产业发展和经济结构的变迁。
《高鸿业微观经济学》课件
供给定理
供给曲线是由生产者的个人行为和市场行为共同决定的。
供给曲线的形成
表示供给量对价格变动的敏感程度，包括点弹性、弧弹性和长期弹性。
供给的价格弹性
弹性是指一个变量对另一个变量的敏感程度，通常用弹性系数来表示。
弹性的概念
表示需求量对价格变动的敏感程度，包括点弹性、弧弹性和长期弹性。
需求的价格弹性
详细描述
市场失灵可能出现的原因包括外部性、公共品、不完全竞争、信息不对称等。在这些情况下，市场无法实现资源的有效配置，需要政府进行干预来纠正市场失灵。政府可以通过税收、补贴、立法等方式来调节市场行为，以实现资源的更优配置。
VS
政府干预并不总是能够解决市场失灵问题，也存在政府失灵的风险。
详细描述
政府失灵可能出现的原因包括政府决策的低效、官僚主义、利益集团的影响等。因此，在实施政府干预时，需要充分考虑其可能带来的副作用和负面影响，并采取相应的措施来减少这些影响。
《高鸿业微观经济学》ppt课件
目录
微观经济学简介供求理论消费者行为理论生产者行为理论市场结构与厂商行为分配理论一般均衡理论与福利经济学
01
微观经济学简介
Chapter
微观经济学是研究个体经济行为和个体经济关系的科学，主要关注个体经济单位（消费者和生产者）的经济行为和决策。
微观经济学主要研究个体经济单位的经济行为和决策，包括消费者的购买行为、生产者的生产决策、市场供求关系、产品价格形成等。它关注个体经济单位如何在资源有限的情况下做出最优决策，以及这些决策如何影响市场结果。
详细描述
总结词
微观经济学的研究方法主要包括实证分析和规范分析、静态分析和动态分析、均衡分析和非均衡分析等。
详细描述
微观经济学名词解释
第一章概论经济学、市场经济学以及价格理论。
指的是采用个量经济法，以市场价格为中心，以主体利益为目标，研究家庭和企业的经济行为，以及怎样通过市场竞争达到资源最优配置。
微观经济学的基本内容：消费理论或需求理论、厂商理论、市场理论、要素价格或分配理论、一般均衡理论和福利经济理论微观经济学的基本假设：a完全理性b完全竞争c完全信息2.宏观经济学：采用总量分析法，以国民收入为中心，以社会福利为目标，研究产品市场、货币市场、劳动市场、国际市场的协调发展，研究怎样通过宏观调控达到资源充分利用。
3.动态分析：又称过程分析，指考虑时间因素对所有均衡状态向新的均衡状态变动过程的分析。
其分析有关经济变量在一定时间内的变化、经济变量在变动过程中的相互联系和相互制约的关系以及他们在每一时刻点上的变动速率等。
蛛网模型是典型的动态分析。
静态分析：即分析经济现象的均衡状态以及有关经济变量处于均衡状态所必须具有的条件，但并不论及达到均衡状态的过程，即完全不考虑时间因素，是一种状态分析，如均衡价格分析。
比较静态分析：指的是分析已知条件变化后经济现象均衡状态的相应变化，以及有关经济变量达到新的均衡状态的相应变化。
第二章需求与供给1.机会成本ch5-1：又称择一成本，指经济资源的稀缺性意味着在给定技术的情况下，将一定资源用于某种用途时所放弃的其他各种用途中的最大收入，或者将一定资源保持在这种用途上必须支付的成本。
2.需求：一种商品的需求是指消费者在一定时期内在各种可能的价格水平愿意而且能够购买的该商品的数量。
需求函数：需求函数是表示一种商品的需求数量和影响该需求数量的各种因素之间的相互关系。
需求函数Q=f(P)表示一种商品的需求量和该商品的价格之间存在着一一对应的关系。
需求价格：指消费者在一定时期内对一定量的某种商品所愿意支付的最高价格。
需求法则：需求量与需求价格反向变动。
3.供给：一种商品的供给是指生产者在一定时期内在各种可能的价格下愿意而且能够提供出售的该商品的数量。
宏微观经济学知识点__概述及说明
宏微观经济学知识点概述及说明引言1.1 概述宏微观经济学是经济学的两个重要分支，旨在研究整体经济现象和个体决策行为对经济体系的影响。
宏观经济学关注国家或地区整体的经济运行和发展，研究各种因素对整体经济活动的影响，如国民生产总值（GDP）、通货膨胀率等。
而微观经济学则关注个体行为与市场交互作用，从供求关系、价格理论、企业竞争等角度研究个体决策对市场产生的影响。
1.2 文章结构本文将按照以下结构进行讨论：第一部分，引言：概述本文的主要内容与目的；第二部分，宏观经济学知识点：详细介绍宏观经济学的相关概念和作用；第三部分，微观经济学知识点：介绍微观经济学中涉及到的市场供求关系、边际效用与边际成本等重要知识点；第四部分，宏观微观经济学的联系与应用：探讨宏观与微观之间的联系，并分析其在政府角色与政策调控、经济增长与发展以及跨国公司和全球化等方面的应用；第五部分，结论：总结文章主要内容，并回顾和展望宏观微观经济学的重要性和应用。
1.3 目的本文旨在帮助读者初步了解宏微观经济学领域中的重要知识点，并展示它们对于理解和解释整体经济现象以及个体决策行为的重要意义。
通过全面梳理宏微观经济学的基础概念和相关应用，读者将能够更好地把握经济运行规律，深入思考相关问题并做出正确决策。
无论是从学术研究还是日常生活实践层面来看，对宏微观经济学知识点的了解都具有重要意义。
这些知识点有助于我们更好地理解市场机制、预测经济趋势、评估政府政策效果以及进行有效决策等各方面的应用。
2. 宏观经济学知识点2.1 定义与作用宏观经济学是研究国家或地区整体经济运行的经济学分支。
它关注的是宏观层面上的经济现象，如总产出、就业水平、通货膨胀等，并探讨其原因和影响。
宏观经济学的主要作用有以下几个方面：- 揭示经济现象背后的规律和机制，帮助我们理解经济运行的本质。
- 提供决策者制定经济政策和管理国家经济的依据。
- 评估和预测国家或地区整体经济发展趋势，为投资者和企业提供参考。
美国高中经济学教材
美国高中经济学教材
美国高中经济学教材，很多国内的学生希望通过先学习美国高中经济学教材为以后走出国门做准备，目前美国的欧桥国际学院已经进入中国，可以通过欧桥学习美国高中经济学。
下面是美国高中经济学教材简介：
课程描述
学生们将研究经济学的各个方面与特定的关注在美国的应用。
课程包括等重大主题类型的经济系统,宏观经济学和微观经济学。
学生将有机会分析和评估这些主题,以及它们是如何联系的。
使用不同的教学方法在本课程包括互动演示,DBQs和研究项目。
课程设计使用最佳实践模型,包括支架、词汇、指导实践,独立实践,和书面回应学生综合的机会,评估,和辩论的话题。
纽约学习标准和单位对齐是利用在本课程建设,以及历史/社会的共同核心素养标准研究,科学和技术学科。
章节
Ch.1-做出选择
Ch.2 -类型的经济系统
Ch.3-微观经济学
Ch.4-生产理论
Ch.5-市场结构
Ch.6-经济机构和问题
Ch.7-研究项目1
Ch.8-政府收入的来源
Ch.9-政府支出
Ch.10-金融市场
Ch.11-宏观经济性能
Ch.12-经济稳定
Ch.13-货币、银行和美国联邦储备理事会(美联储,fed)
Ch.14-经济稳定政策
Ch.15-研究项目2
课程目标
1.评估影响和塑造公众舆论的影响经济政策。
2.检查的影响在经济社会和政治条件。
3.检查角色主要机构如商业、劳动、银行和政府在竞争性的市场结构。
4.分析经济系统、商业组织和经济机构。
5.会认识到我们现在生活在和全球竞争的社会。
尼库尔森《微观经济学》课后答案ch18
CHAPTER 18UNCERTAINTY AND RISK AVERSIONMost of the problems in this chapter focus on illustrating the concept of risk aversion. That is, they assume that individuals have concave utility of wealth functions and therefore dislike variance in their wealth. A difficulty with this focus is that, in general, students will not have been exposed to the statistical concepts of a random variable and its moments (mean, variance, etc.). Most of the problems here do not assume such knowledge, but the Extensions do show how understanding statistical concepts is crucial to reading applications on this topic.Comments on Problems18.1 Reverses the risk-aversion logic to show that observed behavior can be used to placebounds on subjective probability estimates.18.2 This problem provides a graphical introduction to the idea of risk-taking behavior. TheFriedman-Savage analysis of coexisting insurance purchases and gambling could bepresented here.18.3 This is a nice, homey problem about diversification. Can be done graphically althoughinstructors could introduce variances into the problem if desired.18.4 A graphical introduction to the economics of health insurance that examines cost-sharingprovisions. The problem is extended in Problem 19.3.18.5 Problem provides some simple numerical calculations involving risk aversion andinsurance. The problem is extended to consider moral hazard in Problem 19.2.18.6 This is a rather difficult problem as written. It can be simplified by using a particularutility function (e.g., U(W) = ln W). With the logarithmic utility function, one cannot use the Taylor approximation until after differentiation, however. If the approximation isapplied before differentiation, concavity (and risk aversion) is lost. This problem can,with specific numbers, also be done graphically, if desired. The notion that fines aremore effective can be contrasted with the criminologist’s view that apprehension of law-breakers is more effective and some shortcomings of the economic argument (i.e., nodisutility from apprehension) might be mentioned.18.7 This is another illustration of diversification. Also shows how insurance provisions canaffect diversification.18.8 This problem stresses the close connection between the relative risk-aversion parameterand the elasticity of substitution. It is a good problem for building an intuitive9798 Solutions Manualunderstanding of risk-aversion in the state preference model. Part d uses the CRRAutility function to examine the “equity-premium puzzle.”18.9 Provides an illustration of investment theory in the state preference framework.18.10 A continuation of Problem 18.9 that analyzes the effect of taxation on risk-takingbehavior.Solutions18.1 p must be large enough so that expected utility with bet is greater than or equal to thatwithout bet: p ln(1,100,000) + (1 –p)ln(900,000) > ln(1,000,000)13.9108p +13.7102(1 –p) > 13.8155, .2006p > .1053 p > .52518.2This would be limited by the individual’s resources: he or she could run out of wealth since unfair bets are continually being accepted.18.3 a.Strategy One Outcome Probability12 Eggs .50 Eggs .5Expected Value = .5∙12 + .5∙0 = 6Strategy Two Outcome Probability12 Eggs .256 Eggs .50 Eggs .25Expected Value = .25 ∙12 + .5 ∙ 6 + .25∙ 0= 3 + 3 = 6Chapter 18/Uncertainty and Risk Aversion 99b.18.4 a. E(L) = .50(10,000) = $5,000, soWealth = $15,000 with insurance, $10,000 or $20,000 without.b. Cost of policy is .5(5000) = 2500. Hence, wealth is 17,500 with no illness, 12,500with the illness.18.5 a. E(U) = .75ln(10,000) + .25ln(9,000) = 9.1840b. E(U) = ln(9,750) = 9.1850 Insurance is preferable.c. ln(10,000 – p ) = 9.184010,000 – p = e 9.1840 = 9,740p = 26018.6 Expected utility = pU(W – f) + (1 – p)U(W). ,[()()]/U p U pU W f U W p U e p U∂=⋅=--⋅∂,()/U f U fp U W f f U e f U∂'=⋅=-⋅-⋅∂100 Solutions Manual,,()()1()U p U fU W f U W e f U W f e --=<'-- by Taylor expansion,So, fine is more effective.If U (W ) = ln W then Expected Utility = p ln (W – f ) + (1 – p ) ln W .,/[ln ()ln ]U pp p f WW f W e U U -=--⋅≈ ,/()/()U ff p f W f p U W f e U U--=--⋅= ,,1U p U fW fe W e -=<18.7 a. U (wheat) = .5 ln(28,000) + .5 ln(10,000) = 9.7251 U (corn) = .5 ln(19,000) + .5 ln(15,000) = 9.7340 Plant corn. b. With half in eachY NR = 23,500Y R = 12,500U = .5 ln(23,500) + .5 ln(12,500) = 9.7491Should plant a mixed crop. Diversification yields an increased variance relative to corn only, but takes advantage of wheat’s high yield.c. Let α = percent in wheat. U = .5 ln[ (28,000) + (1 – α )(19,000)] + .5 ln[α (10,000) + (1 – α )(15,000)] = .5 ln(19,000 + 9,000α) + .5 ln(15,000 – 5,000α)45002500019,0009,00015,0005,000dU d ααα=-=+- 45(150 – 50α) = 25(190 + 90α) α = .444 U = .5 ln(22,996) + .5 ln(12,780) = 9.7494. This is a slight improvement over the 50-50 mix. d. If the farmer plants only wheat,Y NR = 24,000Y R = 14,000U = .5 ln(24,000) + .5 ln(14,000) = 9.8163so availability of this insurance will cause the farmer to forego diversification.Chapter 18/Uncertainty and Risk Aversion 10118.8 a. A high value for 1 – R implies a low elasticity of substitution between states of theworld. A very risk-averse individual is not willing to make trades away from the certainty line except at very favorable terms.b. R = 1 implies the individual is risk-neutral. The elasticity of substitution between wealth in various states of the world is infinite. Indifference curves are linear with slopes of –1. If R =-∞, then the individual has an infinite relative risk-aversion parameter. His or her indifference curves are L-shaped implying an unwillingness to trade away from the certainty line at any price.c. A rise in b p rotates the budget constraint counterclockwise about the W g intercept. Both substitution and income effects cause W b to fall. There is a substitution effect favoring an increase in W g but an income effect favoring a decline. The substitution effect will be larger the larger is the elasticity of substitution between states (the smaller is the degree of risk-aversion).d. i. Need to find R that solves the equation:R R R W W W )955.0(5.0)055.1(5.0)(000+=This yields an approximate value for R of –3, a number consistent with some empirical studies.ii. A 2 percent premium roughly compensates for a ±10 percent gamble. That is:303030)12.1()92(.)(---+≈W W W .The “puzzle” is that the premium rate of return provided by equities seems to be much higher than this.18.9 a. See graph.Risk free option is R , risk option is R '. b. Locus RR' represents mixed portfolios.c. Risk-aversion as represented by curvature of indifference curves will determine equilibrium in RR' (say E ).102 Solutions Manuald. With constant relative risk-aversion, indifference curve map is homothetic so locus ofoptimal points for changing values of W will be along OE.18.10 a. Because of homothetic indifference map, a wealth tax will cause movement along OE(see Problem 18.9).b. A tax on risk-free assets shifts R inward to Rt (see figure below). A flatter RR t'provides incentives to increase proportion of wealth held in risk assets, especially for individuals with lower relative risk-aversion parameters. Still, as the “note” implies, it is important to differentiate between the after tax optimum and the before taxchoices that yield that optimum. In the figure below, the no-tax choice is E on RR'.* EW represents the locus of points along which the fraction of wealth held in risky assets is constant. With the constraint RR t' choices are even more likely to be to the right of EW* implying greater investment in risky assets.c. With a tax on both assets, budget constraint shifts in a parallel way to RR tt'. Even in this case (with constant relative risk aversion) the proportion of wealth devoted to risky assets will increase since the new optimum will lie along OE whereas a constant proportion of risky asset holding lies along EW O.103。
上财中级微观经济学课件Ch14Consumersurplus
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Intermediate Micro: Consumer Surplus
5
$ Equivalent Utility Gains
Now that she has one gallon, use r2 to denote the most she would pay for a 2nd gallon -this is her reservation price for the 2nd gallon. r2 is the dollar equivalent of the marginal utility of the 2nd gallon.
($) Res. Values
Reservation Price Curve for Gasoline
r 10 1 8 r3 r5 6 4 r7 2 r9 0 r11
$ value of net utility gains-to-trade
pG 1 2 3 4 5 6 7 8 9 10 11
Gasoline (half gallons)
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Intermediate Micro: Consumer Surplus
9
$ Equivalent Utility Gains
($) Res. Values
Reservation Price Curve for Gasoline
r 10 1 8 r2 r3 6 4 r4 2 r5 0 r6
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Intermediate Micro: Consumer Surplus
11
$ Equivalent Utility Gains
微观经济学(高鸿业)完整版
西方经济学第1章 18
4、宏观经济学。
❖ 英国约翰·梅纳德·凯恩斯 John Maynard Keynes （ 1883－ 1946）是现代宏观经济学创始人。
1930年代大危机使传统的自由市场经济理论受到挑战，凯 恩斯于1936年发表了《就业、利息和货币通论》，提出国 家干预经济的思想，标志着现代宏观经济学的产生。
解决的问题是资源配置。Resource allocation
中心理论是价格理论。（看不见的手Invisible hand ） 研究方法是个量分析。研究经济变量的单项数值如何决定
西方经济学第1章 8
2、宏观经济学的特点Macroeconomics
宏观经济学： 研究对象是整个经济。（政府的行为）
研究一个国 家整体经济的
微观经济学
Microeconomics
教材：
主要教材： 西方经济学, 微观部分/ 高鸿业主编 3版。北京 : 中国人民大
学出版社, 2004
参考教材： 现代西方经济学（微观经济学），宋成先著。上海：复旦大
学出版社 微观经济学，梁东黎，刘东编著。南京：南京大学出版社 经济学（上），萨缪尔森，诺德豪斯。中国发展出版社
马歇尔《经济学原理》1890年第一版。 马歇尔综合了边际三杰的成果，提出系统的微观经济理论，
广泛流行于西方。 运用数学方法，从供求角度分析市场价格，以解决资源配置、
资源报酬等问题，主张市场自发调节。
西方经济学第1章 16
新古典主义的 代表人物
西方经济学第1章 17
马歇尔微观经济学的多次补充
第二节 现代西方经济学的由来和演变
❖ 经济学世系图：
曼昆微观经济学(第三版)课后习题答案
Ch1.绪论一、名词解释二、问答题1.微观经济学研究家庭和企业如何作出决策以及这些这些决策在市场上的相互作用。
微观经济学的中心原理是家庭和企业的最优化——他们在目的和所面临的约束条件下可以让自己的景况更好。
而相对的，宏观经济学研究经济的整体情况，它主要关心总产出、总就业、一般物件水平和国际贸易等问题，以及这些宏观指标的波动趋势与规律。
应该看到，宏观经济学研究的这些宏观经济变量是以经济体系中千千万万个体家庭和企业之间的相互作用所构成的。
因此，微观经济决策总是构成宏观经济模型的基础，宏观经济学必然依靠微观经济基础。
2.一般的，模型是对某些具体事物的抽象，经济模型也是如此。
经济模型可以简洁、直接地描述所要研究的经济对象的各种关系。
这样，经济学家可以依赖模型对特定的经济问题进行研究；并且，由于经济实际不可控，而模型是可控的，经济学家可以根据研究需要，合理、科学的调整模型来研究各种经济情况。
另外，经济模型一般是数学模型，而数学是全世界通用的科学语言，使用规范、标准的经济模型也有利于经济学家正确表达自己的研究意图，便于学术交流。
3.略。
请结合您目前所搜集的最新宏观经济新闻进行讨论。
4.市场出清模型就是供给与需求可以在价格机制调整下很快达到均衡的模型。
市场出清模型的前提条件是价格是具有伸缩性的（或弹性）。
但是，我们知道，价格具有伸缩性是一个很强的假设，在很多实际情况下，这个假设都是不现实的。
比如：劳动合同会使劳动力价格在一段时期内具有刚性。
因此，我们必须考虑什么情况下价格具有伸缩性是合适的。
现在一般地认为，在研究长期问题时，假设价格具有伸缩性是合理的；而在研究短期问题时，最好假设价格具有刚性。
因为，从长期看，价格机制终将发挥作用，使市场供需平衡，即市场出清，而在短期，价格机制因其他因素制约，难以很快使市场出清。
5.一般的，人们认为科学的定义是：一种建立稳定关系的科学的研究方法。
比如：物理学家可以通过实验来收集数据，证明或推翻一个假设。
微观经济学 论述题 答案
1、利用图示简要说明微观经济学的理论体系。
Ch2图2-1 产品市场和生产要素市场的循环流动图2、利用图示说明需求价格弹性与总收益之间的关系，及厂商扩大总收益的价格策略。
（以下仅仅图示富有弹性的商品降价，即P1降到P2，与收益的关系；其余类推）。
价格变化、弹性大小与销售收入变化的关系表收益 d e >1 d e =1 d e <1 d e =0 d e =∞降价 增加 不变 减少 同比例于价格的下降而减少既定价格下，收益可以无限增加，因此厂商不会降价 涨价 减少 不变 增加 同比例于价格的上升而增加 收益会减少为零 价格策略降价涨价3、用图示及公式说明序数效用论对消费者均衡的分析。
Ch3消费者均衡是消费者的效用达到最大并维持不变的一种状态。
根据序数效用论，在消费者收入和偏好既定、商品价格不变的条件下，如右图所示，U 1、U 2 、U 3是3条无差异曲线， 分别代表与预算线相交、相切、相离3种情况。
只有预算线AB 和U 2切点E ，才是消费者在给 定的预算约束下能够获得最大效用的均衡点。
相应的最优购买组合为),(*2*1X X 。
用公式表示均衡条件为MRCS 1,2=P 1/P 2。
（3分）因为，就 Q=f(P)O P Q D C B EA e d=∞ e d>1e d=1 e d<1 e d=0 P1P2 Q1 Q2 X X 2abAB*1*2XX 1U 3U 1 U 2 EOU 3来说，虽然它代表的效用水平高于U 2，但消费者在既定的收入水平下无法实现U 3上的 任何一点的商品组合的购买。
就U 1来说，消费者利用现有收入可以购买a 、b 两点的商品组合。
但是，这两点的效用水平低于U 2，因此，理性的消费者不会用全部收入去购买无差异曲线U 1上a 、b 两点的商品组合。
事实上，a 点MRCS 1,2>P 1/P 2 ，b 点MRCS 1,2<P 1/P 2，如消费者能改变购买组合，选择AB 线段上位于a 点右边或b 点左边的任何一商品组合，都可达到比U 1更高的无差异曲线，以获得比a 点和b 点更大的效用水平。
高鸿业《微观经济学》第四版-课后答案(完整版)
《微观经济学》（高鸿业第四版）答案第二章1. 已知某一时期内某商品的需求函数为Q d=50-5P，供给函数为Q s=-10+5p。
（1）求均衡价格P e和均衡数量Q e，并作出几何图形。
（2）假定供给函数不变，由于消费者收入水平提高，使需求函数变为Q d=60-5P。
求出相应的均衡价格P e和均衡数量Q e，并作出几何图形。
（3）假定需求函数不变，由于生产技术水平提高，使供给函数变为Q s=-5+5p。
求出相应的均衡价格P e和均衡数量Q e，并作出几何图形。
（4）利用（1）（2）（3），说明静态分析和比较静态分析的联系和区别。
（5）利用（1）（2）（3），说明需求变动和供给变动对均衡价格和均Q d衡数量的影响.解答:(1)将需求函数d Q= 50-5P和供给函数s Q=-10+5P代入均衡条件d Q= s Q,有:50- 5P= -10+5P得: P e=6以均衡价格P e =6代入需求函数d Q=50-5p ,得:Q e=50-5206=⨯或者,以均衡价格 Pe =6 代入供给函数 s Q =-10+5P ,得: Qe=-10+5206=⨯所以,均衡价格和均衡数量分别为Pe =6 , Qe=20 ...如图1-1所示. (2) 将由于消费者收入提高而产生的需求函数d Q =60-5p 和原供给函数s Q =-10+5P, 代入均衡条件d Q =s Q ,有: 60-5P=-10=5P得7=Pe以均衡价格 7=Pe 代入dQ =60-5p ,得Qe=60-5257=⨯或者,以均衡价格7=Pe 代入sQ =-10+5P, 得Qe=-10+5257=⨯所以,均衡价格和均衡数量分别为7=e P ，25=Qe (3) 将原需求函数d Q =50-5p 和由于技术水平提高而产生的 供给函数Q s =-5+5p ,代入均衡条件d Q =s Q ,有: 50-5P=-5+5P 得 5.5=e P以均衡价格5.5=e P 代入d Q =50-5p ,得5.225.5550=⨯-=e Q或者,以均衡价格5.5=e P 代入s Q =-5+5P ,得5.225.555=⨯+-=e Q所以,均衡价格和均衡数量分别为5.5=e P ，5.22=Qe .如图1-3所示. (4)所谓静态分析是考察在既定条件下某一经济事物在经济变量的相互作用下所实现的均衡状态及其特征.也可以说,静态分析是在一个经Pe-济模型中根据所给的外生变量来求内生变量的一种分析方法.以(1)为例,在图1-1中,均衡点E就是一个体现了静态分析特征的点.它是在给定的供求力量的相互作用下所达到的一个均衡点.在此,给定的供求力量分别用给定的供给函数s Q =-10+5P 和需求函数d Q =50-5p 表示,均衡点E 具有的特征是:均衡价格6=e P 且当6=e P 时,有d Q =s Q =20=Qe ;同时,均衡数量 20=Qe ,切当20=Qe 时,有e s d P P P ==.也可以这样来理解静态分析:在外生变量包括需求函数的参数(50,-5)以及供给函数中的参数(-10,5)给定的条件下,求出的内生变量分别为6=e P ，20=Qe 依此类推,以上所描素的关于静态分析的基本要点,在(2)及其图1-2和(3)及其图1-3中的每一个单独的均衡点()2,1i E 都得到了体现.而所谓的比较静态分析是考察当所有的条件发生变化时,原有的均衡状态会发生什么变化,并分析比较新旧均衡状态.也可以说,比较静态分析是考察在一个经济模型中外生变量变化时对内生变量的影响,并分析比较由不同数值的外生变量所决定的内生变量的不同数值,以(2)为例加以说明.在图1-2中,由均衡点 变动到均衡点 ,就是一种比较静态分析.它表示当需求增加即需求函数发生变化时对均衡点的影响.很清楚,比较新.旧两个均衡点 和 可以看到:由于需求增加由20增加为25.也可以这样理解比较静态分析:在供给函数保持不变的前提下,由于需求函数中的外生变量发生变化,即其中一个参数值由50增加为60,从而使得内生变量的数值发生变化,其结果为,均衡价格由原来的6上升为7,同时,均衡数量由原来的20增加为25.类似的,利用(3)及其图1-3也可以说明比较静态分析方法的基本要求.（5）由(1)和(2)可见,当消费者收入水平提高导致需求增加,即表现为需求曲线右移时,均衡价格提高了,均衡数量增加了.由(1)和(3)可见,当技术水平提高导致供给增加,即表现为供给曲线右移时,均衡价格下降了,均衡数量增加了.总之,一般地有,需求与均衡价格成同方向变动,与均衡数量成同方向变动;供给与均衡价格成反方向变动,与均衡数量同方向变动.2. 假定表2—5是需求函数Qd=500-100P 在一定价格范围内的需求表：某商品的需求表（1）求出价格2元和4元之间的需求的价格弧弹性。
应用经济学一级学科研究生课程简介
应用经济学一级学科研究生课程简介ECON6041 企业管理学Management of Enterprise开课院系：管理学院任课教师：余光胜副教授开课学期：第一学分：3 周学时：3 总学时：54课程性质：硕士学位基础课适用专业：经济学各专业本课程的教学目的掌握产业经济的微观层面的管理问题，提高企业管理的能力，深化企业管理学的研究水平。
教学内容及基本要求本课程针对产业经济学专业的硕士研究生开设，要求具有管理学原理及管理思想史方面的知识背景，本课程将对其进行深入与相关拓展。
主要教学内容包括：1、深化部分：企业管理的核心问题探讨；管理学研究的最新进展；管理学方法论。
2、内容拓展：企业变革管理；企业成长管理；企业知识管理；企业危机管理；企业冲突管理；企业人本管理；企业民主管理；企业契约管理等。
考核方式及要求考试。
课内研讨与课程论文相结合进行课程考核。
学习本课程的前期课程要求具有管理学原理及管理思想史方面的知识背景。
教材及主要参考书目、文献与资料芮明杰，《管理学：现代的观点》，上海人民出版社杨杜，《现代管理理论》，中国人民大学出版社雷恩，《管理思想的演进》，中国社会科学出版社ECON6042 高等应用统计Advanced Applied Statistics开课院系：管理学院任课教师：郑明教授开课学期：第二学分：4 周学时：4 总学时：72课程性质：硕士学位基础课适用专业：经济学各专业本课程的教学目的教学内容及基本要求原理部分：1、假设检验；2、非参数统计推断；3、方差分析；4、多元回归分析；5、判别分析；6、聚类分析；7、时间序列分析。
应用软件：SAS中的有关模块。
根据专业要求和学生基础知识结构情况，在数理统计的原理、应用和软件方面有所兼顾，得到比较全面的训练。
考核方式及要求考试。
闭卷笔试，或辅以中型程序作业。
学习本课程的前期课程要求概率论与初等统计知识。
教材及主要参考书目、文献与资料复旦大学，《概率论》（第二册），人民教育出版社SAS软件研究所上海办事处编，《SAS基础教程》B. E. Wampolo,C. J. Drew, Theory and Application of Statistics.ECON6043 产业经济学Industrial Economics开课院系：管理学院任课教师：郁义鸿教授等开课学期：第二学分：3 周学时：3 总学时：54课程性质：硕士学位基础课适用专业：经济学各专业本课程的教学目的教学内容及基本要求内容：产业部门的概念，部门划分与国民经济核算，产业经济学的三个组成部分：产业结构、产业关联与产业组织及产业经济学体系。
平狄克微观经济学第六版第十四章课后答案解析
CHAPTER 14MARKETS FOR FACTOR INPUTSThe following two chapters examine the markets for labor and capital. Although the discussion in this chapter is general, most of the examples refer to labor as the only variable input to production, with the exception of Example 14.1, which discusses “The Demand for Jet Fuel”by airlines. Labor demand and supply are discussed in the first section, and the competitive factor market equilibrium and economic rent are discussed in the second section. Section 14.3 explores the factor market structure for the case where the buyer has monopsony power, and section 14.4 explores the case of monopoly power on the part of the seller of the factor.An understanding of this chapter relies on concepts from Chapters 4 through 8 and 10. If you have just covered Chapters 11-13, you might begin by reviewing marginal product, marginal revenue, and cost minimization. You should then discuss marginal revenue product and the profit-maximizing condition MRP L = w. Explain why we are only interested in the portion of the MP curve below the average product curve (the downward-sloping portion). The derivation of the firm’s demand curve for labor is straightforward when labor is the only factor, but becomes more complicated when there are several variable inputs. In particular, you might explain why the MRP L curve shifts as the firm substitutes one input for another in production in response to a price change by noting that the MRP L curve is drawn for a fixed level of the other variable input.When presenting the market labor demand curve, explain that since the input prices change as more inputs are demanded, the market demand curve is not simply the summation of individual demand curves. You can extend the presentation of price elasticity of input demand (see Example 14.1) by discussing the conditions leading to price sensitivity. Elasticity is greater (1) when the elasticity of demand for the product is higher, (2) when it is easy to substitute one input for another, and (3) when the elasticity of supply is higher for other inputs. Elasticity of supply, which was discussed in Chapter 2, is reintroduced in Example 14.2. You should also distinguish between short-run and long-run elasticity (see Figure 14.6).If you have already covered substitution and income effects, the students will be ready for the derivation of the backward-bending supply curve for labor. Although Figure 14.9 is a straightforward application of these tools, students are often confused by the plotting of income against leisure. Point out that this is just another type of utility maximization problem where the two goods are leisure and income. Income can be thought of as the consumption of goods other than leisure, in that more income buys more goods. You can also implicitly assume that the price of other goods is $1 and the price of leisure is the wage. The supply of labor curve is derived by changing the wage and finding the new level of hours worked. An individual’s supply curve of labor is backward bending only when the income effect dominates the substitution effect and leisure is a normal good. Show typical supply curves for each group in Table 14.2. For anexperimental study of the labor-leisure trade-off see Battalio, Green, and Kagel, “Income-Leisure Tradeoff of Animal Workers,”American Economic Review (September 1981).Section 14.2 brings together labor demand and supply for both competitive and monopolistic product markets. Although economic rent was presented in Chapter 8, it is reintroduced with more detail here. In Section 14.3, carefully explain why the marginal expenditure curve is above the average expenditure curve for a monopsonist (see Figure 14.14). You can discuss how a monopsonist would price discriminate, e.g., pay a different wage rate to each employee. With perfect price discrimination, the marginal revenue expenditure curve would coincide with the average expenditure curve. Although monopsony exists in some markets, the exercise of monopsony power is rare because of factor mobility. However, the employment of athletes by the owners of professional teams provides a good example (see Example 14.4 “Monopsony Power in the Market for Baseball Players”). On this same topic, see Sommers and Quinton, “Pay and Performance in Major League Baseball: The Case of the First Family of Free Agents,”Journal of Human Resources (Summer 1982). Section 14.4 discusses the case of unions to explore monopoly power on the part of the seller of the input.* *1. Why is a firm’s demand for labor curve more inelastic when the firm has monopoly power in the output market than when the firm is producing competitively?The firm’s demand curve for labor is determined by the incremental revenue fromhiring an additional unit of labor known as the marginal revenue product of labor:MRP L= (MP L)(MR), the additional output (“product”) that the last workerproduced, times the additional revenue earned by selling that output. In acompetitive industry, the marginal revenue curve is perfectly elastic and equal toprice. For a monopolist, marginal revenue is downward sloping. As more labor ishired and more output is produced, the monopolist will charge a lower price andmarginal revenue will diminish. All else the same, marginal revenue product will besmaller for the monopolist. This implies that the marginal revenue product for themonopolist is more inelastic than for the competitive firm.2. Why might a labor supply curve be backward bending?A backward-bending supply curve for labor may occur when the income effect of anincrease in the wage rate dominates the substitution effect. Labor supply decisionsare made by individuals choosing the most satisfying combination of work and other(leisure) activities. With a larger income, the individual can afford to work fewerhours: the income effect. As the wage rate increases, the value of leisure time (theopportunity cost of leisure) increases, thus inducing the individual to work longerhours: the substitution effect. Because the two effects work in opposite directions,the shape of an individual’s labor supply curve depends on the individual’spreferences for income, consumption, and leisure.3. How is a computer company’s demand for computer programmers a derived demand?A computer company’s demand for inputs, including programmers, depends onhow many computers it sells. The firm’s demand for programming labor dependson (is derived from) the demand it faces in its market for computers. As demandfor computers shifts, the demand for programmers shifts.4. Compare the hiring choices of a monopsonistic and a competitive employer of workers. Which will hire more workers, and which will pay the higher wages? Explain.Since the decision to hire another worker means the monopsonist must pay a higherwage for all workers, and not just the last worker hired, its marginal expenditurecurve lies above the input supply curve (the average expenditure curve). Themonopsonist’s profit-maximizing input demand, where the marginal expenditurecurve intersects the marginal revenue product curve, will be less than thecompetitor’s profit-maximizing input choice, where the average expenditure curveintersects the demand curve. The monopsonist hires less labor, and the wage paidwill be less than in a competitive market.5. Rock musicians sometimes earn over $1 million per year. Can you explain such large incomes in terms of economic rent?Economic rent is the difference between the actual payment to the factor ofproduction and the minimum amount that the factor is willing to accept. In thiscase, you might assume that there are a limited number of top-quality rockmusicians who will continue to play rock music no matter what they are paid. Thisresults in a perfectly inelastic supply curve, or something close to it. Given the highdemand for rock music, the wage will be very high and there will be a lot ofeconomic rent. If there was a larger supply of top-quality rock musicians, or a moreelastic supply, then the economic rent would be smaller.6. What happens to the demand for one input when the use of a complementary input increases?If the demand for the complementary input increases, the demand for the giveninput will increase as well. When demand for the complementary input increases,there is an increase in the quantity hired and possibly the price paid. Both of thesechanges will increase the MRP of the given input, and hence will increase thequantity hired and possibly the price paid. Whether the prices of the inputsincreases depends on the degree of monopsony power on the part of the firm.7. For a monopsonist, what is the relationship between the supply of an input and the marginal expenditure on it?The decision to increase employment means the monopsonist must pay all units thehigher price, and not just the last unit hired. Therefore, its marginal expenditurecurve lies above the input supply curve (the average expenditure curve). Hiringmore labor will increase the marginal expenditure, which will increase the averageexpenditure. If the average expenditure is increasing, then the marginalexpenditure must be greater than the average expenditure.8. Currently the National Football League has a system for drafting college players by which each player is picked by only one team. The player must sign with that team or not play in the league. What would happen to the wages of newly drafted and more experienced football players if the draft system were repealed, and all teams could compete for college players?The National Football League draft and reserve clause (a primary issue in the 1987-1988 season’s strike) creates a monopsonist cartel among the owners of NFL teams.If the draft system were repealed, competition among teams would increase wagesof football players to the point where the marginal revenue product of each playerwould be equal to the player’s wage.9. The government wants to encourage individuals on welfare to become employed. It is considering two possible incentive programs for firms.A. Give the firm $2 per hour for every individual on welfare who is hired.B. Give each firm that hires one or more welfare workers a payment of $1000 peryear, irrespective of the number of hires.To what extent is each of these programs likely to be effective at increasing the employment opportunities for welfare workers?Firms will hire additional labor as long as the extra benefit is greater than the extracost of hiring the worker, or until MRP L = w. Option A would be effective becauseif the firm receives $2 per hour for every welfare worker hired then the effectivewage paid, w, will fall and the firm will find it optimal to hire more labor until thebenefits (MRP L) again equal the costs (w) at the margin. Option B would beeffective at increasing employment opportunities also in that if the firm hires anindividual who has been on welfare they will then receive $1000. However, plan Bis not necessarily as effective as plan A given the firm only receives one lump sumpayment regardless of the number of welfare workers hired. In this case the firmonly has an incentive to hire the one welfare worker, though they may of coursechoose to hire more than one welfare worker.10. A small specialty cookie company, whose only variable input is labor, finds that the average worker can produce 50 cookies per day, the cost of the average worker is $64 per day, and the price of a cookie is $1. Is the cookie company maximizing its profit? Explain.The marginal product of labor is 50 (cookies per day) and the price per cookie is 1($ per cookie) so the marginal revenue product is $50/day. Since this is less thanthe wage of $64 per day the cookie company is not maximizing profit. They areemploying too much labor since the cost of labor is greater than the benefit oflabor at the margin, and are therefore producing too many cookies.11. A firm uses both labor and machines in production. Explain why an increase in the average wage rate causes both a movement along the labor demand curve and a shift of the curve.An increase in the wage rate causes an upward movement along the labordemand curve. For any given marginal revenue product curve, the firm will findthat they want to hire fewer workers when the wage increases (an upwardmovement). However, when the wage increases the marginal cost will increasewhich will reduce desired output. When output falls, the firm will not need asmany machines and the marginal product of labor curve will shift to the left,assuming machines and labor are complementary. This will also reduce thedemand for labor.1. Suppose that the wage rate is $16 per hour, and the price of the product is $2. Values for output and labor are in units per hour.q L0 020 135 247 357 465 570 6a.Find the profit-maximizing quantity of labor.From the information given above, calculate the marginal product of labor, theextra output produced by hiring one more unit of labor, and then multiply by priceto get the marginal revenue product of labor. To find the profit-maximizingquantity of labor, use the rule that the firm wants to hire labor only as long as themarginal revenue product of labor is greater than the nominal wage, or up to thepoint where the marginal revenue product of labor is equal to the nominal wage.From the table below, the firm will hire 5 units of labor.b.Suppose that the price of the product remains at $2 but that the wage rate increasesto $21. Find the new profit-maximizing quantity of labor.The above table does not change for this part of the problem. However, the firmno longer wants to hire 5 units of labor because the benefit of the 5th unit ($16 perhour) is less than the cost of the 5th unit ($21 per hour). The firm would only hire3 units of labor per hour since in this case the benefit still exceeds the cost at themargin. The firm would stick with 3 units instead of 4 unless fractional units arepossible. At L=4 the cost is greater than the benefit so you lose profit by hiringthe 4th unit of labor.c.Suppose the price of the product increases to $3 and the wage remains at $16 perhour. Find the new profit-maximizing quantity of labor.A change in the price of the product will not change the marginal product of labor,but it will change the marginal revenue product of labor. The new marginalrevenue product of labor is given in the table below. The firm will still want tohire 5 units of labor, as in part a above. It will not hire the 6th unit because theextra benefit is less than the extra cost. Profit will be greater than in part a.d.Suppose that the price of the product remains at $2 and the wage remains at $16, butthere is a technological breakthrough that increases output by 25% for any given level of labor. Find the new profit-maximizing quantity of labor.The technological breakthrough changes the number of units of output producedby a given number of units of labor, and hence changes the marginal product andthe marginal revenue product of labor. The new output values are found bymultiplying the old values by 1.25. This new information is given in the tablebelow. The firm will still choose to hire 5 units of labor. Profit will be greaterthan in part a.2. Assume that workers whose incomes are less than $10,000 currently pay no federal income taxes. Suppose a new government program guarantees each worker $5,000, whether or not he or she earns any income. For all earned income up to $10,000, the worker must pay a 50-percent tax. Draw the budget line facing the workers under this new program. How is the program likely to affect the labor supply curve of workers?The budget line for workers under this program is a straight line at $5,000. This lineis shown in the figure and table below. Workers earn $5,000 whether they work ornot. If workers work only to earn income, i.e., there are no other benefits such as“getting out of the house”or “gaining experience,”there is no incentive towork under the new program. Only wages yielding incomes greater than $10,000will result in a positive labor supply.Figure 14.2Income After TaxIncome GovernmentSubsidyTotalIncome0 0 5,000 $5,000$1,000 500 4,500 5,0002,000 1,000 4,000 5,0003,000 1,500 3,500 5,0004,000 2,000 3,000 5,0005,000 2,500 2,500 5,0006,000 3,000 2,000 5,0007,000 3,500 1,500 5,0008,000 4,000 1,000 5,0009,000 4,500 500 5,00010,000 5,000 0 5,0003. Using your knowledge of marginal revenue product, explain the following:a. A famous tennis star is paid $100,000 for appearing in a 30-second televisioncommercial. The actor who plays his doubles partner is paid $500.Marginal revenue product of labor, MRP L, is equal to marginal revenue from anincremental unit of output multiplied by the marginal product from an incrementalunit of labor, or in other words, the extra revenue generated by having the tennisstar appear in the ad. The famous tennis star is able to help increase revenues farmore than the actor, so he is paid much more than the actor. The wage of theactor is determined by the supply and demand of actors willing to play tennis withtennis stars.b. The president of an ailing savings and loan is paid not to stay in his job for the last twoyears of his contract.The marginal revenue product of the president of the ailing savings and loan is likelyto be negative and therefore, the savings and loan is better off by paying thepresident not to show up. They have calculated that they will lose less (or gainmore) by paying the president off and hiring someone else.c. A jumbo jet carrying 400 passengers is priced higher than a 250-passenger model eventhough both aircraft cost the same to manufacture.The ability of the larger jet to generate more revenue increases its value to theairline, and therefore the airline is willing to pay more for it.4. The demands for the factors of production listed below have increased. What can you conclude about changes in the demand for the related consumer goods? If demands for the consumer goods remain unchanged, what other explanation is there for an increase in derived demands for these items?a. Computer memory chipsIn general, an increase in the demand for a good increases the demand for its factorinputs. The converse is not necessarily true; i.e., an increase in the demand forfactor inputs does not necessarily imply an increase in the demand for the finalproduct. The demand for an input may increase due to a change in the use ofother inputs in the production process. As the price of another input increases, itsdemand falls and the demand of substitutable inputs rises. In this case, the increasein the demand for computer memory chips must have been caused by an increase inthe demand for personal computers given that computer memory chips are usedonly in computers, and there are no substitutes for computer memory chips.b. Jet fuel for passenger planesWith an increase in the demand for jet travel, the demand for jet fuel will increase.There are no substitutes for jet fuel.c. Paper used for newsprintGiven the paper is being used to print newspapers then there must have been anincrease in the circulation of newspapers.d. Aluminum used for beverage cansWith an increase in demand for cold drinks in the summer, the seasonal demand foraluminum increases, so this is one possible explanation. Alternatively, if glass orplastic have become more expensive then this may affect the demand for aluminum.Finally, changes in the market for recycled aluminum may affect the demand fornew aluminum.5. Suppose there are two groups of workers, unionized and nonunionized. Congress passesa law that requires all workers to join the union. What do you expect to happen to the wage rates of formerly nonunionized workers? of those workers who were originally unionized? What have you assumed about the union’s behavior?In general, we expect that nonunionized workers are earning lower wages thanunionized workers. If all workers are forced to join the union, it would bereasonable to expect that the nonunionized workers will now receive higher wagesand the unionized workers will receive a wage that could go either way. There are acouple of items to consider. First, the union now has more monopoly power in thatthere are no nonunion workers to act as substitutes for union workers. This givesmore power to the union, which means higher wages can in general be negotiated.However, the union now has more members to satisfy. If wages are kept at a highlevel, there will be fewer jobs, and hence some previously nonunionized workersmay end up with no job. The union may wish to trade off some of the wage for aguarantee of more jobs. The average income of all workers will rise if labor demandis inelastic and will fall if labor demand is elastic.6. Suppose a firm’s production function is given by Q = 12L - L2, for L = 0 to 6, where L is labor input per day and Q is output per day. Derive and draw the firm’s demand for labor curve if the firm’s output sells for $10 in a competitive market. How many workers will the firm hire when the wage rate is $30 per day? $60 per day? (Hint: The marginal product of labor is 12 - 2L.)The demand for labor is given by the marginal revenue product of labor. This isequal to the product of marginal revenue and the marginal product of labor: MRP L =(MR)(MP L). In a competitive market, price is equal to marginal revenue, so MR = 10.We are given MP L = 12 - 2L (the slope of the production function).Figure 14.6Therefore, the MRP L = (10)(12 - 2L). The firm’s profit-maximizing quantity of laboroccurs where MRP L = w. If w = 30, then 30 = 120 - 20L at the optimum. Solving forL yields 4.5 hours per day. Similarly, if w = 60, solving for L yields 3 hours per day.7. The only legal employer of military soldiers in the United States is the federal government. If the government uses its monopsonistic position, what criteria will it employ when figuring how many soldiers to recruit? What happens if a mandatory draft is implemented?Acting as a monopsonist in hiring soldiers, the federal government would hiresoldiers until the marginal value of the last soldier is equal to his or her pay. Thereare two implications of the government’s monopsony power: fewer soldiers arehired, and they are paid less than their marginal product. When a mandatory draftis implemented, even fewer professional soldiers are hired. Wages for volunteersoldiers fall, pushed down by the fact that wages of the draftees can be very low.8. The demand for labor by an industry is given by the curve L = 1200 - 10w, where L is the labor demanded per day and w is the wage rate. The supply curve is given by L = 20w. Whatis the equilibrium wage rate and quantity of labor hired? What is the economic rent earned by workers?The equilibrium wage rate is determined where quantity of labor supplied is equal tothe quantity of labor demanded:20w = 1,200 - 10w, or w = $40.Substituting into either the labor supply or labor demand equations, we find theequilibrium quantity of labor is 800:L= (20)(40) = 800,SandL D = 1,200 - (10)(40) = 800.Economic rent is the summation of the difference between the equilibrium wage andthe wage given by the labor supply curve. Here, it is the area above the laborsupply curve up to L = 800 and below the equilibrium wage. This triangle’s area is(0.5)(800)($40) = $16,000.9. This exercise is a continuation of Exercise 8. Suppose now that the only labor available is controlled by a monopolistic labor union that wishes to maximize the rent earned by union members. What will be the quantity of labor employed and the wage rate? How does your answer compare with your answer to Exercise 8? Discuss. (Hint: The union’s marginal revenue curve is given by L = 1200 - 20w.)Recall that the monopolist chooses output by setting marginal revenue equal to themarginal cost of supplying one more unit of output, as opposed to the competitivefirm which chooses output by setting price equal to marginal cost, or in other wordsproducing where supply intersects demand. The monopolistic labor union acts inthe same way. To maximize rent in this case, the union will choose the number ofworkers hired so that the marginal revenue to the union (the additional wagesearned) is equal to the extra cost of inducing the worker to work. This involveschoosing the quantity of labor at the point where the marginal revenue curvecrosses the supply curve of labor. Note that the marginal revenue curve has twicethe slope of the labor demand curve. Marginal revenue is less than the wage,because when more workers are hired, all workers receive a lower wage.Setting the marginal revenue curve equal to the supply curve for labor, we find:1200 - 20w = 20w, or w* = 30.At w*, we may determine the number of workers who are willing to work bysubstituting w* into the labor supply equation:L * = (20)(30) = 600.Therefore, if the union wants to maximize the rent that the union members earn, theunion should limit employment to 600 members.To determine the wage the members will earn, substitute L * into the labor demandequation:600 = 1,200 - 10w , or w = 60.The total rent the employed union members will receive is equal to:Rent = (60 - 30)(600) + (0.5)(30)(600) = $27,000.Notice that the wage is higher and the number of workers employed is lower than in Exercise (8).*10. A firm uses a single input, labor, to produce output q according to the production function. The commodity sells for $150 per unit and the wage rate is $75 per hour.a. Find the profit-maximizing quantity of L.There are two (equivalent) methods of solving this problem. Most generally,define the profit function, where revenues and costs are expressed in terms of theinput, calculate the first order necessary condition (the first derivative of the profitfunction), and solve for the optimal quantity of the input. Alternatively, use therule that the firm will hire labor up until the point where the marginal revenueproduct (p*MP L ) equals the wage rate. Using the first method:π=TR -TC =pq -wLπ=150*8*L 12-75L∂π∂L=600L -12-75=0L =64.b. Find the profit-maximizing quantity of q.From part a, the profit maximizing quantity of labor is 64 so substitute thisquantity of labor into the production function to find q =8L 12=8*64=64. c. What is the maximum profit?Profit is total revenue minus total cost or π=150*64-75*64=4800.d. Suppose now that the firm is taxed $30 per unit of output and the wage rate issubsidized at a rate of $15 per hour. Assume the firm is a price taker, so that theprice of the product remains at $150. Find the new profit-maximizing levels of L, q, and profit.After the $30 tax per unit of output is paid, the firm receives 150-30=$120 per unitof output sold. This is the relevant price for the profit maximizing decision. The input cost is now 75-15=$60 per unit labor after the subsidy is received. The profit maximizing values can be found as in parts a-c above:TR-TC=pq-wLp=120*8*L12-60L¶p¶L=480L-12-60=0L=64q=64p=3840.e.Now suppose that the firm is required to pay a 20% tax on its profits. Find the newprofit-maximizing levels of L, q, and profit.The profit maximizing values can be found as in parts a-c above, only here profit is80% of total revenue minus total cost.π=.8(TR-TC)=.8(pq-wL)π=.8(150*8*L12-75L)∂π∂L=480L-12-60=0L=64q=64π=3840.。
微观经济中的价格歧视与消费者剩余
微观经济中的价格歧视与消费者剩余在微观经济学的广袤领域中，价格歧视与消费者剩余是两个关键且相互关联的概念。
它们不仅影响着企业的定价策略，也深刻地左右着消费者的福利和市场的效率。
价格歧视，简而言之，是指企业对同一种商品或服务向不同的消费者收取不同的价格。
这可不是简单的随意定价，而是基于一系列复杂的因素和策略。
比如说，按照消费者的购买数量来定价。
我们去超市购物，经常能看到“买一送一”“第二件半价”等促销活动，这其实就是一种数量上的价格歧视。
对于那些购买量大的消费者，商家给予了更低的单位价格，因为他们能带来更大的销售额和利润。
再比如，按照消费者的支付意愿来进行价格歧视。
常见的例子就是飞机票和火车票。
同样的行程，商务舱和经济舱的价格差异巨大。
这是因为商务旅客通常对价格不太敏感，更注重舒适和便捷，他们愿意支付更高的价格；而对于经济舱的旅客，价格则相对较低，以吸引更多对价格敏感的消费者。
还有一种基于消费者身份的价格歧视。
学生、老年人、军人等特殊群体在很多场合都能享受到优惠价格。
这是因为企业认为这些群体的支付能力相对较弱，或者出于社会责任感和政策要求，给予他们一定的价格优惠。
价格歧视看起来似乎对企业有利，能够让企业赚取更多的利润，但实际上，它也并非完全没有风险和限制。
首先，实施价格歧视需要企业对市场和消费者有深入的了解，否则可能会出现误判，导致策略失败。
其次，价格歧视可能会引起消费者的不满和反感，如果被消费者察觉并认为不公平，可能会损害企业的声誉和品牌形象。
接下来，我们再来谈谈消费者剩余。
消费者剩余是指消费者在购买某种商品或服务时，愿意支付的价格与实际支付的价格之间的差额。
比如说，你特别喜欢一款新出的手机，心理预期愿意支付 5000 元，但实际上它的售价只有 4000 元，那么这 1000 元的差额就是你的消费者剩余。
消费者剩余反映了消费者在市场交易中的福利水平。
当市场竞争充分，价格合理时，消费者剩余往往较大，消费者能够享受到更多的实惠。
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9
Profit =
MR – MC $6 4 2 0 –2
6 8 10 12
4 5
40 50
33 45
FIRMS IN COMPETITIVE MARKETS
If
shut down in SR, must still pay FC. If exit in LR, zero costs.
12
FIRMS IN COMPETITIVE MARKETS
A FIRM’S SHORT-RUN DECISION TO SHUT DOWN
Cost of shutting down: revenue loss = TR
P1
Q
11
FIRMS IN COMPETITIVEБайду номын сангаасMARKETS
SHUTDOWN VS. EXIT
Shutdown: A short-run decision not to produce anything because of market conditions. Exit: A long-run decision to leave the market. A key difference:
Because of 1 & 2, each buyer and seller is a
“price taker” – takes the price as given.
3
FIRMS IN COMPETITIVE MARKETS
THE REVENUE OF A COMPETITIVE FIRM
15
FIRMS IN COMPETITIVE MARKETS
A FIRM’S LONG-RUN DECISION TO EXIT
Cost of exiting the market: revenue loss = TR
Benefit of exiting the market: cost savings = TC (zero FC in the long run)
Chapter 14
FIRMS IN COMPETITIVE MARKET 竞争市场上的企业
Economics
PRINCIPLES OF
N. Gregory Mankiw
IN THIS CHAPTER, LOOK FOR THE ANSWERS TO THESE QUESTIONS:
What is a perfectly competitive market? What is marginal revenue? How is it related to total and average revenue? How does a competitive firm determine the quantity that maximizes profits? When might a competitive firm shut down in the short run? Exit the market in the long run? What does the market supply curve look like in the short run? In the long run?
At Q1, MC = MR. Changing Q would lower profit.
P1
MR
Qa Q 1 Qb
Q
10
FIRMS IN COMPETITIVE MARKETS
MC AND THE FIRM’S SUPPLY DECISION
If price rises to P2, then the profitmaximizing quantity rises to Q2. The MC curve determines the firm’s Q at any price. Hence, the MC curve is the firm’s supply curve. Q1 Q2 Costs MC P2 MR2 MR
MC AND THE FIRM’S SUPPLY DECISION
Rule: MR = MC at the profit-maximizing Q. At Qa, MC < MR. So, increase Q to raise profit. Costs MC
At Qb, MC > MR. So, reduce Q to raise profit.
Enter if P > ATC
17
FIRMS IN COMPETITIVE MARKETS
THE COMPETITIVE FIRM’S SUPPLY CURVE
The firm’s LR supply curve is the portion of its MC curve above LRATC.
2
FIRMS IN COMPETITIVE MARKETS
CHARACTERISTICS OF PERFECT COMPETITION
1. 2. 3.
Many buyers and many sellers. The goods offered for sale are largely the same. Firms can freely enter or exit the market.
3
4 5
$10
$10 $10
$10
$10 $10 $10
6
FIRMS IN COMPETITIVE MARKETS
MR = P FOR A COMPETITIVE FIRM
A competitive firm can keep increasing its output without affecting the market price. So, each one-unit increase in Q causes revenue to rise by P, i.e., MR = P.
Fill in the empty spaces of the table.
Q 0 1 2 P $10 $10 $10 TR = P x Q $0 $10 AR = TR Q MR = ∆TR
∆Q
n/a $10 $10
Notice that $20 $10 MR = P
$30
$40 $50
$10
$10 $10
1
FIRMS IN COMPETITIVE MARKETS
INTRODUCTION: A SCENARIO
Three years after graduating, you run your own business. You must decide how much to produce, what price to charge, how many workers to hire, etc. What factors should affect these decisions? Your costs (studied in preceding chapter) How much competition you face We begin by studying the behavior of firms in perfectly competitive markets.
So, firm exits if TR < TC
Divide both sides by Q to write the firm’s Exit if P < ATC decision rule as:
16
FIRMS IN COMPETITIVE MARKETS
A NEW FIRM’S DECISION TO ENTER MARKET
Total revenue (TR)
Average revenue (AR)
TR = P x Q
TR =P AR = Q ∆TR MR = ∆Q
Marginal revenue (MR): The change in TR from selling one more unit.
4
ACTIVE LEARNING
In the long run, a new firm will enter the market if it is profitable to do so: if TR > TC. Divide both sides by Q to express the firm’s entry decision as:
13
TR/Q < VC/Q
FIRMS IN COMPETITIVE MARKETS
A COMPETITIVE FIRM’S SR SUPPLY CURVE
The firm’s SR Costs supply curve is the portion of its MC curve If .P > AVC, then above AVC firm produces Q where P = MC.
8
FIRMS IN COMPETITIVE MARKETS
PROFIT MAXIMIZATION
(continued from earlier exercise)
At any Q with MR > MC, increasing Q raises profit. At any Q with MR < MC, reducing Q raises profit.