平狄克微观经济学课件(英文)10

Fernando&YvonnQuijanoPreparedby:MarketPower:MonopolyandMonopsony10CHAPTERCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.Chapter10:MarketPower:MonopolyandMonopsony2of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.CHAPTER10OUTLINE10.1Monopoly10.2MonopolyPower10.3SourcesofMonopolyPower10.4TheSocialCostsofMonopolyPower10.5Monopsony10.6MonopsonyPower10.7LimitingMarketPower:TheAntitrustLawsChapter10:MarketPower:MonopolyandMonopsony3of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.●monopolyMarketwithonlyoneseller.●monopsonyMarketwithonlyonebuyer.●marketpowerAbilityofasellerorbuyertoaffectthepriceofagood.MarketPower:MonopolyandMonopsonyChapter10:MarketPower:MonopolyandMonopsony4of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1AverageRevenueandMarginalRevenue●marginalrevenueChangeinrevenueresultingfromaone-unitincreaseinoutput.TABLE10.1Total,Marginal,andAverageRevenueTotalMarginalAveragePrice(P)Quantity(Q)Revenue(R)Revenue(MR)Revenue(AR)$60$0------515$5$54283433913248-12155-31Chapter10:MarketPower:MonopolyandMonopsony5of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1AverageRevenueandMarginalRevenueAverageandmarginalrevenueareshownforthedemandcurveP=6−Q.AverageandMarginalRevenueFigure10.1Chapter10:MarketPower:MonopolyandMonopsony6of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1TheMonopolist’sOutputDecisionQ*istheoutputlevelatwhichMR=MC.Ifthefirmproducesasmalleroutput—say,Q1—itsacrificessomeprofitbecausetheextrarevenuethatcouldbeearnedfromproducingandsellingtheunitsbetweenQ1andQ*exceedsthecostofproducingthem.Similarly,expandingoutputfromQ*toQ2wouldreduceprofitbecausetheadditionalcostwouldexceedtheadditionalrevenue.ProfitIsMaximizedWhenMarginalRevenueEqualsMarginalCostFigure10.2Chapter10:MarketPower:MonopolyandMonopsony7of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1TheMonopolist’sOutputDecisionWecanalsoseealgebraicallythatQ*maximizesprofit.Profitπisthedifferencebetweenrevenueandcost,bothofwhichdependonQ:AsQisincreasedfromzero,profitwillincreaseuntilitreachesamaximumandthenbegintodecrease.Thustheprofit-maximizingQissuchthattheincrementalprofitresultingfromasmallincreaseinQisjustzero(i.e.,Δπ/ΔQ=0).ThenButΔR/ΔQismarginalrevenueandΔC/ΔQismarginalcost.Thustheprofit-maximizingconditionisthat,orChapter10:MarketPower:MonopolyandMonopsony8of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1AnExamplePart(a)showstotalrevenueR,totalcostC,andprofit,thedifferencebetweenthetwo.Part(b)showsaverageandmarginalrevenueandaverageandmarginalcost.Marginalrevenueistheslopeofthetotalrevenuecurve,andmarginalcostistheslopeofthetotalcostcurve.Theprofit-maximizingoutputisQ*=10,thepointwheremarginalrevenueequalsmarginalcost.Atthisoutputlevel,theslopeoftheprofitcurveiszero,andtheslopesofthetotalrevenueandtotalcostcurvesareequal.Theprofitperunitis$15,thedifferencebetweenaveragerevenueandaveragecost.Because10unitsareproduced,totalprofitis$150.ExampleofProfitMaximizationFigure10.3Chapter10:MarketPower:MonopolyandMonopsony9of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1ARuleofThumbforPricingWewanttotranslatetheconditionthatmarginalrevenueshouldequalmarginalcostintoaruleofthumbthatcanbemoreeasilyappliedinpractice.Todothis,wefirstwritetheexpressionformarginalrevenue:Chapter10:MarketPower:MonopolyandMonopsony10of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1ARuleofThumbforPricingNotethattheextrarevenuefromanincrementalunitofquantity,Δ(PQ)/ΔQ,hastwocomponents:1.ProducingoneextraunitandsellingitatpricePbringsinrevenue(1)(P)=P.2.Butbecausethefirmfacesadownward-slopingdemandcurve,producingandsellingthisextraunitalsoresultsinasmalldropinpriceΔP/ΔQ,whichreducestherevenuefromallunitssold(i.e.,achangeinrevenueQ[ΔP/ΔQ]).Thus,Chapter10:MarketPower:MonopolyandMonopsony11of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.MONOPOLY10.1ARuleofThumbforPricing(Q/P)(ΔP/ΔQ)isthereciprocaloftheelasticityofdemand,1/Ed,measuredattheprofit-maximizingoutput,andNow,becausethefirm’sobjectiveistomaximizeprofit,wecansetmarginalrevenueequaltomarginalcost:whichcanberearrangedtogiveus(10.1)Equivalently,wecanrearrangethisequationtoexpresspricedirectlyasamarkupovermarginalcost:(10.2)Chapter10:MarketPower:MonopolyandMonopsony12of50Copyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Microeconomics•Pindyck/Rubinfeld,7e.In1995,Prilosec,representedanewgenerationofantiulcermedication.Prilosecwasbasedonaverydifferentbiochemicalmechanismandwasmuchmoreeffec