曼昆微观经济学 第五版 第五章 课文PPT

ElasticityandItsApplicationChapter5Copyright©2001byHarcourt,Inc.Allrightsreserved.Requestsforpermissiontomakecopiesofanypartoftheworkshouldbemailedto:PermissionsDepartment,HarcourtCollegePublishers,6277SeaHarborDrive,Orlando,Florida32887-6777.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.Elasticity...…isameasureofhowmuchbuyersandsellersrespondtochangesinmarketconditions…allowsustoanalyzesupplyanddemandwithgreaterprecision.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.PriceElasticityofDemandPriceelasticityofdemandisthepercentagechangeinquantitydemandedgivenapercentchangeintheprice.Itisameasureofhowmuchthequantitydemandedofagoodrespondstoachangeinthepriceofthatgood.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.DeterminantsofPriceElasticityofDemandNecessitiesversusLuxuriesAvailabilityofCloseSubstitutesDefinitionoftheMarketTimeHorizonHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.DeterminantsofPriceElasticityofDemandDemandtendstobemoreelastic:ifthegoodisaluxury.thelongerthetimeperiod.thelargerthenumberofclosesubstitutes.themorenarrowlydefinedthemarket.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ComputingthePriceElasticityofDemandThepriceelasticityofdemandiscomputedasthepercentagechangeinthequantitydemandeddividedbythepercentagechangeinprice.PriceElasticityofDemand=PercentageChangeinQuantityDemandedPercentageChangeinPricePriceElasticityofDemand=PercentageChangeinQuantityDemandedPercentageChangeinPriceHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ComputingthePriceElasticityofDemandpriceinchangePercentagedemandedquatityinchangePercentagedemandofelasticityPriceExample:Ifthepriceofanicecreamconeincreasesfrom$2.00to$2.20andtheamountyoubuyfallsfrom10to8conesthenyourelasticityofdemandwouldbecalculatedas:2percent10percent2010000200220210010810.)..()(Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ComputingthePriceElasticityofDemandUsingtheMidpointFormulaThemidpointformulaispreferablewhencalculatingthepriceelasticityofdemandbecauseitgivesthesameanswerregardlessofthedirectionofthechange.)/2]P)/[(PP(P)/2]Q)/[(QQ(Q=DemandofElasticityPrice12121212Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ComputingthePriceElasticityofDemandExample:Ifthepriceofanicecreamconeincreasesfrom$2.00to$2.20andtheamountyoubuyfallsfrom10to8conestheyourelasticityofdemand,usingthemidpointformula,wouldbecalculatedas:32.25.9222/)20.200.2()00.220.2(2/)810()810(percentpercent)/2]P)/[(PP(P)/2]Q)/[(QQ(Q=DemandofElasticityPrice12121212Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.RangesofElasticityInelasticDemandQuantitydemandeddoesnotrespondstronglytopricechanges.Priceelasticityofdemandislessthanone.ElasticDemandQuantitydemandedrespondsstronglytochangesinprice.Priceelasticityofdemandisgreaterthanone.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ComputingthePriceElasticityofDemandDemandispriceelastic$54DemandQuantity1000Price50-3percent22-percent675.00)/2(4.005.00)-(4.0050)/2(10050)-(100EDHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.RangesofElasticityPerfectlyInelasticQuantitydemandeddoesnotrespondtopricechanges.PerfectlyElasticQuantitydemandedchangesinfinitelywithanychangeinprice.UnitElasticQuantitydemandedchangesbythesamepercentageastheprice.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.AVarietyofDemandCurvesBecausethepriceelasticityofdemandmeasureshowmuchquantitydemandedrespondstotheprice,itiscloselyrelatedtotheslopeofthedemandcurve.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.PerfectlyInelasticDemand-Elasticityequals0QuantityPrice4$5Demand1002....leavesthequantitydemandedunchanged.1.Anincreaseinprice...Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.InelasticDemand-Elasticityislessthan1QuantityPrice4$51.A22%increaseinprice...Demand100902....leadstoa11%decreaseinquantity.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.UnitElasticDemand-Elasticityequals1QuantityPrice4$51.A22%increaseinprice...Demand100802....leadstoa22%decreaseinquantity.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ElasticDemand-Elasticityisgreaterthan1QuantityPrice4$51.A22%increaseinprice...Demand100502....leadstoa67%decreaseinquantity.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.PerfectlyElasticDemand-ElasticityequalsinfinityQuantityPriceDemand$41.Atanypriceabove$4,quantitydemandediszero.2.Atexactly$4,consumerswillbuyanyquantity.3.Atapricebelow$4,quantitydemandedisinfinite.Harcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.ElasticityandTotalRevenueTotalrevenueistheamountpaidbybuyersandreceivedbysellersofagood.Computedasthepriceofthegoodtimesthequantitysold.TR=PxQHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.$4DemandQuantityP0PricePxQ=$400(totalrevenue)100QElasticityandTotalRevenueHarcourt,Inc.itemsandderiveditemscopyright©2001byHarcourt,Inc.Elastici