第章競爭市場上的企業(yè)曼昆經(jīng)濟(jì)學(xué)原理第七版PPT課件

1、Firms in Competitive Markets 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.1What is a Co

2、mpetitive Market?Competitive marketPerfectly competitive marketMarket with many buyers and sellersTrading identical productsEach buyer and seller is a price takerFirms can freely enter or exit the market 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole

3、or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.2What is a Competitive Market?Firm in a competitive marketTries to maximize profit ProfitTotal revenue minus total costTotal revenue, TR =

4、 P QPrice times quantity Proportional to the amount of output 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected websit

5、e for classroom use.3What is a Competitive Market?Average revenue, AR = TR / QTotal revenue divided by the quantity soldMarginal revenue, MR = TR / QChange in total revenue from an additional unit soldFor competitive firmsAR = PMR = P 2015 Cengage Learning. All Rights Reserved. May not be copied, sc

6、anned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.4Table 15 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole o

7、r in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.Total, Average, and Marginal Revenue for a Competitive FirmProfit MaximizationMaximize profitProduce quantity where total revenue minus tot

8、al cost is greatestCompare marginal revenue with marginal costIf MR MC: increase productionIf MR MC, firm should increase outputIf MC MR, firm should decrease outputIf MR = MC, profit-maximizing level of outputMarginal-cost curveDetermines the quantity of the good the firm is willing to supply at an

9、y priceIs the supply curve 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.10Figure 211 20

10、15 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.Marginal Cost as the Competitive Firms Suppl

11、y CurvePrice An increase in the price from P1 to P2 leads to an increase in the firms profit-maximizing quantity from Q1 to Q2. Because the marginal-cost curve shows the quantity supplied by the firm at any given price, it is the firms supply curve.Quantity 0ATCAVCMCP1P2Q2Q1Profit MaximizationShutdo

12、wnShort-run decision not to produce anythingDuring a specific period of timeBecause of current market conditionsFirm still has to pay fixed costsExitLong-run decision to leave the marketFirm doesnt have to pay any costs 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or dupli

13、cated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.12Profit MaximizationThe firms short-run decision to shut downTR = total revenueVC = variable costsFirms decision:Shut dow

14、n if TR VC (P AVC,.2. .butshuts downif PAVC.Profit MaximizationSunk costA cost that has already been committed and cannot be recoveredShould be ignored when making decisions“Dont cry over spilt milk”“Let bygones be bygones”In the short run, fixed costs are sunk costs 2015 Cengage Learning. All Right

15、s Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.15Near-empty restaurants & off-season miniature golfRestaurant stay open f

16、or lunch?Fixed costsNot relevantAre sunk costs in short runVariable costs relevantShut down if revenue from lunch variable costs16 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a c

17、ertain product or service or otherwise on a password-protected website for classroom use.Staying open can be profitable, even with many tables empty.Near-empty restaurants & off-season miniature golfOperator of a miniature-golf courseIgnore fixed costsShut down if Revenue variable costs17 2015 Cenga

18、ge Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.Profit MaximizationFirms long-run decisionExit the m

19、arket if Total revenue total costs; TR TCSame as: P total costs; TR TCSame as: P ATCCompetitive firms long-run supply curveThe portion of its marginal-cost curve that lies above average total cost 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in p

20、art, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.18Figure 419 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permit

21、ted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.The Competitive Firms Long-Run Supply CurveCostsIn the long run, the competitive firms supply curve is its marginal-costcurve (MC) above average total cost (ATC). If the pric

22、e falls below average total cost, the firm is better off exiting the market.Quantity 0MC1. In the long run, the firm produces on the MC curve if PATC,.2. .but exits if P ATCProfit = TR TC = (P ATC) QIf P AVC: supply curve is MC curveMarket supplyAdd up quantity supplied by each firm 2015 Cengage Lea

23、rning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.22Figure 623 2015 Cengage Learning. All Rights Reserved. M

24、ay not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.Short-Run Market SupplyPriceIn the short run, the number of firms in the market is fixe

25、d. As a result, the market supply curve, shown in panel (b), reflects the individual firms marginal-cost curves, shown in panel (a). Here, in a market of 1,000 firms, the quantity of output supplied to the market is 1,000 times the quantity supplied by each firm.Quantity(firm) 0(a) Individual firm s

26、upplyMC100$2.00PriceQuantity(market) 0(b) Market supply2001.00Supply100,000$2.00200,0001.00Supply CurveLong runFirms can enter and exit the marketIf P ATC, firms make positive profitNew firms enter the marketIf P ATC positive economic profit 2015 Cengage Learning. All Rights Reserved. May not be cop

27、ied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.28Supply CurvePositive economic profit in short runLong run firms enter the marketShort run supply c

28、urve shifts rightPrice decreases back to minimum ATCQuantity increases Because there are more firms in the marketEfficient scale 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a cer

29、tain product or service or otherwise on a password-protected website for classroom use.29Figure 830 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or ot

30、herwise on a password-protected website for classroom use.An Increase in Demand in the Short Run and Long Run (a)PricePriceThe market starts in a long-run equilibrium, shown as point A in panel (a). In this equilibrium, each firm makes zero profit, and the price equals the minimum average total cost.Quantity(market) 0MarketQuantity(firm) 0FirmATCMC(a) I