【正文】 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. THE INDUSTRY’S LONGRUN SUPPLY CURVE IncreasingCost Industry ● increasingcost indus。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. CHOOSING OUTPUT IN THE LONG RUN Firms Earn Zero Profit in LongRun Equilibrium In longrun equilibrium, all firms earn zero economic profit. In (a), a baseball team in a moderatesized city sells enough tickets so that price ($7) is equal to marginal and average cost. In (b), the demand is greater, so a $10 price can be charged. The team increases sales to the point at which the average cost of production plus the average economic rent is equal to the ticket price. When the opportunity cost associated with owning the franchise(專營權(quán) )is taken into account, the team earns zero economic profit. Figure Producer Surplus in the Long Run Chapter 8: Profit Maximization and Competitive Supply 48 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. CHOOSING OUTPUT IN THE LONG RUN LongRun Competitive Equilibrium The Opportunity Cost of Land There are other instances in which firms earning positive accounting profit may be earning zero economic profit. Suppose, for example, that a clothing store happens to be located near a large shopping center. The additional flow of customers can substantially increase the store’s accounting profit because the cost of the land is based on its historical cost. Economic Rent ● economic rent Amount that firms are willing to pay for an input less the minimum amount necessary to obtain it. Chapter 8: Profit Maximization and Competitive Supply 46 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. CHOOSING OUTPUT IN THE LONG RUN LongRun Competitive Equilibrium Entry and Exit In a market with entry and exit, a firm enters when it can earn a positive longrun profit and exits when it faces the prospect of a longrun loss. ● longrun petitive equilibrium All firms in an industry are maximizing profit, no firm has an incentive to enter or exit, and price is such that quantity supplied equals quantity demanded. A longrun petitive equilibrium occurs when three conditions hold: 1. All firms in the industry are maximizing profit. 2. No firm has an incentive either to enter or exit the industry because all firms are earning zero economic profit. 3. The price of the product is such that the quantity supplied by the industry is equal to the quantity demanded by consumers. Chapter 8: Profit Maximization and Competitive Supply 44 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. 廠商與市場的協(xié)調(diào) Q P Q P D S1 AC MC（ S） …… S2 S D P* 廠商的情況 市場的情況 Chapter 8: Profit Maximization and Competitive Supply 42 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. CHOOSING OUTPUT IN THE LONG RUN LongRun Competitive Equilibrium Accounting Profit and Economic Profit π = R ? wL ? rK Zero Economic Profit ● zero economic profit A firm is earning a normal return on its investment—., it is doing as well as it could by investing its money elsewhere. Chapter 8: Profit Maximization and Competitive Supply 40 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. CHOOSING OUTPUT IN THE LONG RUN LongRun Profit Maximization Output Choice in the Long Run The firm maximizes its profit by choosing the output at which price equals longrun marginal cost LMC. In the diagram, the firm increases its profit from ABCD to EFGD by increasing its output in the long run. Figure The longrun output of a profitmaximizing petitive firm is the point at which longrun marginal cost equals the price. Chapter 8: Profit Maximization and Competitive Supply 38 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. THE SHORTRUN MARKET SUPPLY CURVE Producer Surplus in the Short Run Producer Surplus for a Market The producer surplus for a market is the area below the market price and above the market supply curve, between 0 and output Q*. Figure Producer Surplus versus Profit Producer surplus = PS = R ? VC Profit = π = R ? VC ? FC Chapter 8: Profit Maximization and Competitive Supply 36 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. THE SHORTRUN MARKET SUPPLY CURVE The ShortRun World Supply of Copper The supply curve for world copper is obtained by summing the marginal cost curves for each of the major copperproducing countries. The supply curve slopes upward because the marginal cost of production ranges from a low of 65 cents in Russia to a high of $ in Canada. Figure Chapter 8: Profit Maximization and Competitive Supply 34 of 36 Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall ? Microeconomics ? Pindyck/Rubinfeld, 7e. 價格上升對行業(yè)供應量的影響 ? 產(chǎn)品價格上升有兩種效應 ： – 產(chǎn)品供應量增加 – 原材料成本上升， MC上升，供應曲線內(nèi)移動，供應量降低（ 中國資源依賴型經(jīng)濟增長帶動原材料價格上漲，進一步阻礙中國經(jīng)濟增長） ? 行業(yè)供應曲線反應的是這兩者的中和 Chapter 8: Profit Maximization and Competitive Supply 32 of 36 Copy