Chap_14竞争市场中的企业课件

Click to edit Master title style,,Click to edit Master text styles,,Second Level,,Third Level,,Fourth Level,,Fifth Level,,Harcourt, Inc. items and derived items copyright © 2001 by Harcourt, Inc.,Firms in Competitive Markets,竞争市场中的企业,Chapter 14,WHAT IS A COMPETITIVE MARKET?,,A,perfectly competitive market,has the following characteristics:,,There are many buyers and sellers in the market.,,The goods offered by the various sellers are largely the same.,,Firms can freely enter or exit the market.,什么是竞争市场？,完全竞争市场,有以下特点,:,,市场中有许多买者和许多卖者。

各个卖者所提供的物品大体上是相同的企业可以自由地进入或退出市场WHAT IS A COMPETITIVE MARKET?,As a result of its characteristics, the,perfectly competitive market,has the following outcomes:,,The actions of any single buyer or seller in the market have a negligible impact on the market price.,,each buyer and seller is,a price taker.,,什么是竞争市场？,由于以上特点,,完全竞争市场,具有以下结果,:,,市场上任何一个买者或卖者的行动对市场价格的影响都可以忽略不计每一个买者和卖者都是价格的接受者,The Revenue of a Competitive Firm,竞争企业的收益,Total revenue,for a firm is the,selling price,times the,quantity sold,.,,一个企业的,总收益,等于销售价格乘以销售量。

TR = (P,X,Q),The Revenue of a Competitive Firm,Average revenue,tells us how much revenue a firm receives for the typical unit sold.,The Revenue of a Competitive Firm,In perfect competition,,,average revenue,equals the price of the good.,The Revenue of a Competitive Firm,竞争企业的收益,Marginal revenue,is the change in total revenue from an additional unit sold.,,边际收益,是增加一个单位销售量,,所引起的总收益变化MR =,,TR/,,Q,The Revenue of a Competitive Firm,竞争企业的收益,For competitive firms,,marginal revenue,equals the price of the good.,,对竞争企业来说，,边际收益,等于,,物品的销售价格。

表1. 竞争企业的总收益、平均收益和边际收益,Profit Maximization and the Competitive Firm’s Supply Curve,The goal of a competitive firm is to,maximize profit.,,This means that the firm will want to produce the quantity that maximizes the,difference between total revenue and total cost,.,利润最大化与竞争企业的供给曲线,竞争企业的目标是,利润最大化这就意味着企业想生产某一产量，使总收益与总成本的差最大表2. 利润最大化: 一个数字例子,Figure 1 Profit Maximization for a Competitive Firm,Copyright © 2004 South-Western,Quantity,0,Costs,and,Revenue,MC,ATC,AVC,MC,1,Q,1,MC,2,Q,2,The firm maximizes,profit by producing,the quantity at which,marginal cost equals,marginal revenue.,Q,MAX,,P,=,MR,1,=,MR,2,,P,=,AR,=,MR,Profit Maximization for the Competitive Firm,竞争企业的利润最大化,Profit maximization,occurs at the quantity where marginal revenue equals marginal cost.,,当边际收益等于边际成本时，企业实现,利润最大化。

Profit Maximization for the Competitive Firm,When MR > MC,,increase,Q,When MR < MC, de,crease,Q,When MR = MC, Profit is maximized.,Figure 2 Marginal Cost as the Competitive Firm’s Supply Curve,Quantity,0,Price,MC,ATC,AVC,P,1,Q,1,P,2,Q,2,This section of the,,firm’s,MC,curve is,,also the firm’s supply,,curve.,The Firm’s Short-Run Decision to Shut Down,（停止营业）,A,shutdown,refers to a short-run decision not to produce anything during a specific period of time because of current market conditions.,,Exit,refers to a long-run decision to leave the market.,企业的短期停止营业决策,停止营业,是指在某个特殊时期由于当前的市场条件而不生产任何东西的短期决策。

退出,是指离开市场的长期决策The Firm’s Short-Run Decision to Shut Down,The firm considers its,sunk costs,when deciding to exit, but ignores them when deciding whether to shut down.,,Sunk costs,are costs that have already been committed and cannot be recovered.,企业的短期停止营业决策,当决定退出时，企业考虑,沉淀成本；,当决定是否停止营业时企业应忽略沉淀成本沉淀成本,是已经发生而且无法收回,（并与当前决策无关）,的成本The Firm’s Short-Run Decision to Shut Down,The firm shuts down if the revenue it gets from producing is less than the variable cost of production.,,Shut down if TR < VC,,Shut down if P < AVC,企业的短期停止营业决策,如果生产能得到的收益小于生产的可变成本，企业就停止营业。

如果,TR < VC，,停止营业如果,P < AVC，,停止营业Figure 3 The Competitive Firm’s Short Run Supply Curve,MC,Quantity,ATC,AVC,0,Costs,Firm,shuts,down if,P,<,AVC,Firm,’,s short-run,supply curve,If,P,>,AVC,,firm will continue to produce in the short run.,If,P,>,ATC,, the firm will continue to produce at a profit.,The Firm’s Long-Run Decision to Exit or Enter a Market,In the long-run, the firm exits if the revenue it would get from producing is less than its total cost.,,Exit if TR < TC,,Exit if P < ATC,企业进入或退出一个市场的长期决策,在长期中，如果从生产中得到的收益小于生产的总成本,企业就退出。

如果,TR < TC，,就退出如果,P < ATC，,就退出The Firm’s Long-Run Decision to Exit or Enter a Market,A firm will enter the industry if such an action would be profitable.,,,Enter if TR > TC,,,,Enter if P > ATC,利润,Q,图5. 作为价格与平均总成本之间面积的利润,产量,0,价格,,P = AR = MR,ATC,MC,P,ATC,利润最大化产量,a.,有利润企业 ——新企业进入市场,亏损,图5. 作为价格与平均总成本之间面积的利润,产量,0,价格,P = AR = MR,ATC,MC,P,Q,亏损最小化产量,ATC,b.,亏损企业 ——退出市场,Figure 7 Market Supply with Entry and Exit,(,a) Firm,’,s Zero-Profit Condition,Quantity (firm),0,Price,(,b) Market Supply,Quantity (market),Price,0,P,=,minimum,ATC,Supply,MC,ATC,The Long Run: Market Supply with Entry and Exit,Firms will enter or exit the market until profit is driven to zero.,,In the long run, price equals the minimum of average total cost.,,The long-run market supply curve is horizontal at this price.,长期：有进入与退出的市场供给,企业进入或退出市场，直到经济利润为零。

在长期中，价格等于最小平均总成本长期市场供给曲线是这一价格时的水平线The Long Run: Market Supply with Entry and Exit,Long-run equilibrium must have firms operating at their efficient scale.,,,竞争市场长期均衡一定是企业在其有效规模时运行Why Do Competitive Firms Stay in Business If They Make Zero Profit?,,Profit equals total revenue minus total cost.,,Total cost includes all the opportunity costs of the firm.,,In the zero-profit equilibrium, the firm’s revenue compensates the owners for the time and money they expend to keep the business going.,如果竞争企业获得零利润，为什么它们还在经营？,利润等于总收益减总成本。

总成本包括企业的所有机会成本在零利润均衡时，企业的收益应该补偿所有者期望用于使其企业维持的时间和金钱Marginal Firm,,边际企业,,The,marginal firm,is the firm that would exit the market if the price were any lower.,,,边际企业——,如果价格有任何下降就退出市场的企业Summary,Because a competitive firm is a price taker, its revenue is proportional to the amount of output it produces.,,The price of the good equals both the firm’s average revenue and its marginal revenue.,小结,因为竞争企业是价格接受者，所以它的收益与产量是同比例的物品的价格等于企业的平均收益和边际收益Summary,To maximize profit a firm chooses the quantity of output such that marginal revenue equals marginal cost.,,,This is also the quantity at which price equals marginal cost.,,Therefore, the firm’s marginal cost curve is its supply curve.,小结,为了利润最大化，企业选择使边际收益等于边际成本的产量。

这一产量也是价格等于边际成本的产量因此，企业的边际成本曲线就是它的供给曲线Summary,In the short run when a firm cannot recover its fixed costs, the firm will choose to shut down temporarily 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.,小结,在短期中，当企业不能收回其固定成本时，如果物品价格小于平均可变成本，企业将选择停止营业在长期中，如果价格小于平均总成本，企业不能收回其固定成本和可变成本，企业将选择退出市场Summary,In a market with free entry and exit, profits are driven to zero in the long run and all firms produce at the efficient scale.,小结,在可以自由进入与退出的市场中，长期利润为零，所有企业在有效规模时生产。