MBA管理经济学PPT课件.ppt

Chapter11ManagerialDecisionsinCompetitiveMarkets,LearningObjectives,Discuss3characteristicsofperfectlycompetitivemarketsExplainwhythedemandcurvefacingaperfectlycompetitivefirmisperfectlyelasticandservesasthefirmsmarginalrevenuecurveFindshortrunprofitmaximizingoutput,derivefirmandindustrysupplycurves,andidentifyproducersurplusExplaincharacteristicsoflongruncompetitiveequilibriumforafirm,derivelongrunindustrysupply,andidentifyeconomicrentandproducersurplusFindtheprofitmaximizinglevelofavariableinputEmployempiricallyestimatedvaluesofmarketprice,averagevariablecost,andmarginalcosttocalculateprofitmaximizingoutputandprofit,PerfectCompetition,Firmsareprice-takersEachproducesonlyaverysmallportionoftotalmarketorindustryoutputAllfirmsproduceahomogeneousproductEntryintoalwaysupwardslopingSupplypricesgivemarginalcostsofproductionforeveryfirm,Short-RunProducerSurplus,Short-runproducersurplusistheamountbywhichTRexceedsTVCTheareaabovetheshort-runsupplycurvethatisbelowmarketpriceovertherangeofoutputsuppliedExceedseconomicprofitbytheamountofTFC,ComputingShort-RunProducerSurplus(Figure11.6),Short-RunFirm&IndustrySupply(Figure11.6),Long-RunProfit-MaximizingEquilibrium(Figure11.7),Profit=($17-$12)x240=$1,200,Long-RunCompetitiveEquilibrium,Allfirmsareinprofit-maximizingequilibrium(P=LMC)Occursbecauseofentry/exitoffirmsin/outofindustryMarketadjustssoP=LMC=LAC,Long-RunCompetitiveEquilibrium(Figure11.8),Long-RunIndustrySupply,Long-runindustrysupplycurvecanbeflat(perfectlyelastic)orupwardslopingDependsonwhetherconstantcostindustryorincreasingcostindustryEconomicprofitiszeroforallpointsonthelong-runindustrysupplycurveforbothtypesofindustries,ConstantcostindustryAsindustryoutputexpands,inputpricesremainconstant,&minimumLACisunchangedP=minimumLAC,socurveishorizontal(perfectlyelastic)IncreasingcostindustryAsindustryoutputexpands,inputpricesrise,&minimumLACrisesLong-runsupplypricerises&curveisupwardsloping,Long-RunIndustrySupply,Long-RunIndustrySupplyforaConstantCostIndustry(Figure11.9),Long-RunIndustrySupplyforanIncreasingCostIndustry(Figure11.10),Firmsoutput,EconomicRent,Paymenttotheownerofascarce,superiorresourceinexcessoftheresourcesopportunitycostInlong-runcompetitiveequilibriumfirmsthatemploysuchresourcesearnzeroeconomicprofitPotentialeconomicprofitispaidtotheresourceaseconomicrentInincreasingcostindustries,alllong-runproducersurplusispaidtoresourcesuppliersaseconomicrent,EconomicRentinLong-RunCompetitiveEquilibrium(Figure11.11),Profit-MaximizingInputUsage,Profit-maximizinglevelofinputusageproducesexactlythatlevelofoutputthatmaximizesprofit,Marginalrevenueproduct(MRP)MRPofanadditionalunitofavariableinputistheadditionalrevenuefromhiringonemoreunitoftheinput,Ifchoosetoproduce:IftheMRPofanadditionalunitofinputisgreaterthanthepriceofinput,thatunitshouldbehiredEmployamountofinputwhereMRP=inputprice,Profit-MaximizingInputUsage,Averagerevenueproduct(ARP)Averagerevenueperworker,ShutdowninshortrunifARPMRPWhenARPMRP,TRTVC,Profit-MaximizingInputUsage,Profit-MaximizingLaborUsage(Figure11.12),ImplementingtheProfit-MaximizingOutputDecision,Step1:ForecastproductpriceUsestatisticaltechniquesfromChapter7Step2:EstimateAVC&SMCAVC=a+bQ+cQ2SMC=a+2bQ+3cQ2,Step3:CheckshutdownruleIfPAVCminthenproduceIfPAVCminthenshutdownTofindAVCminsubstituteQminintoAVCequation,ImplementingtheProfit-MaximizingOutputDecision,Step4:IfPAVCmin,findoutputwhereP=SMCSetforecastedpriceequaltoestimatedmarginalcost&solveforQ*,ImplementingtheProfit-MaximizingOutputDecision,P=a+2bQ*+3cQ*2,Step5:ComputeprofitorlossProfit=TRTC=PxQ*-AVCxQ*-TFC=(PAVC)Q*-TFC,IfPAVCmin,firmshutsdown&profitis-TFC,ImplementingtheProfit-MaximizingOutputDecision,Profit&LossatBeauApparel(Figure11.13),Profit&LossatBeauApparel(Figure11.13),Summary,Perfectcompetitorsareprice-takers,producehomogenousoutput,andhavenobarrierstoentryThedemandcurveforaperfectlycompetitivefirmisperfectlyelastic(orhorizontal)atthemarketdeterminedequilibriumprice,andmarginalrevenueequalspriceManagersmaketwodecisionsintheshortrun:(1)produceorshutdown,and(2)ifproduce,howmuchtoproduceWhenpositiveprofitispossible,profitismaximizedattheoutputwhereP=SMCWhenmarketpricefallsbelowminimumAVCthefirmshutsdownandproducesnothing,losingonlyTFC,Summary,Inlong-runcompetitiveequilibrium,allfirmsareinprofit-maximizingequilibrium(P=LMC)Noincentiveforfirmstoenterorexittheindustrybecauseeconomicprofitiszero(P=LAC)ChoosingeitheroutputorinputusageleadstothesameoptimaloutputdecisionandprofitlevelFive