管理经济学英文版最新版教学课件第8章

CHAPTER8ManaginginCompetitive,Monopolistic,andMonopolisticallyCompetitiveMarketsChapterOutline•Perfectcompetition–Demandatthemarketandfirmlevels–Short-runoutputdecisions–Long-rundecisions•Monopoly–Monopolypower–Sourcesofmonopolypower–Maximizingprofits–Implicationsofentrybarriers•Monopolisticcompetition–Conditionsformonopolisticcompetition–Profitmaximization–Long-runequilibrium–Implicationsofproductdifferentiation•Optimaladvertisingdecisions8-2ChapterOverviewIntroduction•Chapter7examinedthenatureofindustries,andsawthatindustriesdifferwithrespecttotheirstructures,conductsandperformances.•Thischapterfocusesonhowmanagersdeterminetheoptimalprice,quantityandadvertisingdecisionsinthefollowingmarketenvironments:–Perfectcompetition.–Monopoly.–Monopolisticcompetition.8-3ChapterOverviewKeyConditions•Perfectlycompetitivemarketsarecharacterizedby:–Theinteractionbetweenmanybuyersandsellersthatare“small”relativetothemarket.–Eachfirminthemarketproducesahomogeneous(identical)product.–Buyersandsellershaveperfectinformation.–Notransactioncosts.–Freeentryintoandexitfromthemarket.•Theimplicationsoftheseconditionsare:–asinglemarketpriceisdeterminedbytheinteractionofdemandandsupply–firmsearnzeroeconomicprofitsinthelongrun.8-4PerfectCompetitionDemandattheMarketandFirmLevelsInAction8-5PerfectCompetitionMarketoutput0Price𝑃𝑒𝐷𝑓=𝑃𝑒DPriceFirm’soutputSMarketFirmShort-RunOutputDecisions•Theshortrunisaperiodoftimeoverwhichsomefactorsofproductionarefixed.•Tomaximizeshort-runprofits,managersmusttakeasgiventhefixedinputs(andfixedcosts),anddeterminehowmuchoutputtoproducebychangingthevariableinputs.8-6PerfectCompetitionShort-RunProfitMaximization:Revenue-CostApproachInAction8-7PerfectCompetitionFirm’soutput$0Revenue𝑅=𝑃×𝑄ABSlopeof𝐶𝑄=𝑀𝐶ECosts𝐶𝑄Slopeof𝑅=𝑀𝑅=𝑃Maximumprofits𝑄∗CompetitiveFirm’sDemand•Thedemandcurveforacompetitivefirm’sproductisahorizontallineatthemarketprice.Thispriceisthecompetitivefirm’smarginalrevenue.𝐷𝑓=𝑃=𝑀𝑅8-8PerfectCompetitionShort-RunProfitMaximizationInAction8-9PerfectCompetitionFirm’soutput$0𝑄∗𝑃𝑒𝑀𝐶𝐴𝑇𝐶𝐷𝑓=𝑃𝑒=𝑀𝑅𝐴𝑇𝐶𝑄∗ProfitCompetitiveOutputRule•Tomaximizeprofits,aperfectlycompetitivefirmproducestheoutputatwhichpriceequalsmarginalcostintherangeoverwhichmarginalcostisincreasing.𝑃=𝑀𝐶𝑄8-10PerfectCompetitionCompetitiveOutputRuleInAction•Thecostfunctionforafirmis𝐶𝑄=5+𝑄2.Ifthefirmsellsoutputinaperfectlycompetitivemarketandotherfirmsintheindustryselloutputatapriceof$20,whatpriceshouldthemanagerofthisfirmcharge?Whatlevelofoutputshouldbeproducedtomaximizeprofits?Howmuchprofitwillbeearned?•Answer:–Charge$20.–Sincemarginalcostis2𝑄,equatingpriceandmarginalcostyields:$20=2𝑄⟹𝑄=10units.–Maximumprofitsare:𝜋=20×10−5+102=$95.8-11PerfectCompetitionShort-RunLossMinimizationInAction8-12PerfectCompetitionFirm’soutput$0𝑄∗𝑃𝑒𝑀𝐶𝐴𝑇𝐶𝐷𝑓=𝑃𝑒=𝑀𝑅Loss𝐴𝑇𝐶𝑄∗𝐴𝑉𝐶TheShut-DownCaseInAction8-13PerfectCompetitionFirm’soutput$0𝑄∗𝑃𝑒𝑀𝐶𝐴𝑇𝐶𝐷𝑓=𝑃𝑒=𝑀𝑅FixedCost𝐴𝑇𝐶𝑄∗𝐴𝑉𝐶𝐴𝑉𝐶𝑄∗LossifproduceLossifshutdownShort-RunOutputDecision•Tomaximizeshort-runprofits,aperfectlycompetitivefirmshouldproduceintherangeofincreasingmarginalcostwhere𝑃=𝑀𝐶,providedthat𝑃≥𝐴𝑉𝐶.If𝑃𝐴𝑉𝐶,thefirmshouldshutdownitsplanttominimizeitlosses.8-14PerfectCompetitionShort-RunFirmSupplyCurveInAction8-15PerfectCompetitionFirm’soutput$0𝑄0𝑃0𝑀𝐶𝐴𝑉𝐶𝑃1𝑄1Short-runsupplycurveforindividualfirmFirm’sShort-RunSupplyCurve•Theshort-runsupplycurveforaperfectlycompetitivefirmisitsmarginalcostcurveabovetheminimumpointonthe𝐴𝑉𝐶curve.8-16PerfectCompetitionMarketSupplyCurveInAction8-17PerfectCompetitionMarketoutputP01$10$12MarketsupplycurveIndividualfirm’ssupplycurve𝑀𝐶𝑖500SLong-RunDecisions:EntryandExitInAction8-18PerfectCompetitionMarketoutput0Price𝑃0𝐷𝑓=𝑃0=𝑀𝑅0DPriceFirm’soutput𝑆0𝑆1𝑃1𝑆2𝐷𝑓=𝑃1=𝑀𝑅1𝐷𝑓=𝑃2=𝑀𝑅2𝐸𝑛𝑡𝑟𝑦𝐸𝑥𝑖𝑡𝑃20ExitEntryLong-RunCompetitiveEquilibriumInAction8-19PerfectCompetitionFirm’soutput$0𝑄∗𝑃𝑒𝑀𝐶𝐴𝐶𝐷𝑓=𝑃𝑒=𝑀𝑅Long-runcompetitiveequilibriumLong-RunCompetitiveEquilibrium•Inthelongrun,perfectlycompetitivefirmsproducealevelofoutputsuchthat𝑃=𝑀𝐶𝑃=𝑚𝑖𝑛𝑖𝑚𝑢𝑚𝑜𝑓𝐴𝐶8-20PerfectCompetitionMonopolyandMonopolyPower•Amarketstructureinwhichasinglefirmservesanentiremarketforagoodthathasnoclosesubstitutes.•Solesellerofagoodinamarketgivesthatfirmgreatermarketpowerthanifitcompetedagainstotherfirms.–Implication:•marketdemandcurveisthemonopolist’sdemandcurve.–However,amonopolistdoesnothaveunlimitedmarketpower.8-21MonopolyMonopolist’sDemandInAction8-22MonopolyOutputPrice0𝑃0𝐷𝑓=𝐷𝑀𝑃1𝑄1𝑄0ABMonopolist’spowerisconstrainedbythedemandcurve.SourcesofMonopolyPower•Economiesofscale•Economiesofscope•Costcomplementarity•Patentsandotherlegalbarriers8-23MonopolyElasticityofDemandandTotalRevenuesInAction8-24MonopolyQ0Revenue𝑃0𝑄0PriceFirm’soutput0𝑄0UnitaryUnitaryElasticInelasticInelasticElasticMaximumrevenues𝑃0×𝑄0𝑅0MRDTotalRevenueCurveMarginalRevenueandElasticity•Themonopolist’smarginalrevenuefunctionis𝑀𝑅=𝑃1+𝐸𝐸,where𝐸istheelasticityofdemandforthemonopolist’sproductand𝑃isthepricechar