中微15-16章教学讲解课件

MICROECONOMICSⅡ

微观经济学ⅡZHOUJimei周吉梅InternationalBusinessSchoolMICROECONOMICSⅡ

微观经济学ⅡZHOUJi1Chapter15MarketDemandChapter15MarketDemand2OutlineIndividualandmarketdemandElasticityElasticityandRevenueElasticityandMarginalrevenueLaffercurveOutlineIndividualandmarket3MarketdemandOftenthinkofmarketbehavinglikeasingleindividualrepresentativeconsumermodelTogetmarketdemand,justaddupindividualdemandshorizontalsummationprincipleInverseofaggregatedemandcurvemeasurestheMRSforeachindividualMarketdemandOftenthinkofma4Q(a)Adam’sdemandPDADADEDE(b)PQEva’sdemandP1QAQEQ(A+E)(c)AtanygivenpricePD(A+E)D(A+E)Q+=marketdemandQ(a)Adam’sdemandPDADADEDE(b)P5NumericalexampleSupposetheinverseofthedomesticdemandfunctionP=40-Q/3Now,addanexportdemandP=60–QWhat’sthetotalmarketdemand?NumericalexampleSupposethe62.ElasticitymeasuresresponsivenessofdemandtopriceCanweuseslopetomeasuretheresponsiveness?Elasticityisabetterway:independentofunitsofmeasurementThepriceelasticityofdemandε=(dq/q)/(dp/p)=(p/q)/(dp/dq)=slopeoftheray/slopeofthecurve2.Elasticitymeasuresresponsi7ExampleforlineardemandcurvepiXi*api=a-bXi*a/ba/2a/2b|ε|>1|ε|<1Exampleforlineardemandcurv8QuestionIstheredemandfunctionwhosepriceelasticityisalwaysconstantalongthisdemandcurve?Supposedemandtakesformq=ApbOtherexpressionofelasticityQuestionIstheredemandfunct9Otherelasticityincomeelasticityofdemandcross-priceelasticityofdemandown-priceelasticityofsupplyOtherelasticityincomeelastic103.ElasticityandRevenueSellers’revenueisSo3.ElasticityandRevenueSelle11ElasticityandRevenuesoifthenandachangetopricedoesnotalter

sellers’revenue.ElasticityandRevenuesoifthe12ElasticityandRevenuebutifthenandapriceincreaseraisessellers’

revenue.ElasticityandRevenuebutifth13ElasticityandRevenueAndifthenandapriceincreasereducessellers’

revenue.ElasticityandRevenueAndifth14SummaryOwn-priceinelasticdemand;

pricerisecausesriseinsellers’revenue.Own-priceunitelasticdemand;

pricerisecausesnochangeinsellers’

revenue.Own-priceelasticdemand;

pricerisecausesfallinsellers’revenue.SummaryOwn-priceinelasticde154.ElasticityandMarginalRevenueAseller’smarginalrevenueistherateatwhichrevenuechangeswiththenumberofunitssoldbytheseller.4.ElasticityandMarginalRe16ElasticityandMarginalRevenuep(q)denotestheseller’sinversedemandfunction;i.e.thepriceatwhichthesellercansellqunits.ThensoElasticityandMarginalRevenu17ElasticityandMarginalRevenueandsoElasticityandMarginalRevenu18Sellingone

moreunitraisestheseller’srevenue.Sellingone

moreunitreducestheseller’srevenue.Sellingone

moreunitdoesnotchangetheseller’s

revenue.SummaryIfthenIfthenIfthen

19AlinearexampleAnexamplewithlinearinversedemand.ThenandAlinearexampleAnexamplewit20aa/bpqa/2baa/bpqa/2b21PQQElasticity,marginalrevenueandrevenueD(AR)BA

elasticEd＝(-)1inelasticMR0CMaximumP*×Q*

elasticinelastic0P*Q*revenuePQQElasticity,marginalrevenu22Laffercurvehowdoestaxrevenuerespondtochangesintaxrates?Howtoconstructthemodel?Laffercurvehowdoestaxreven23中微15-16章教学讲解课件24中微15-16章教学讲解课件25Chapter16

EquilibriumChapter16Equilibrium26OutlineMarketEquilibriumSpecialcasesTaxes:niceexampleofcomparativestaticsPassingalongataxDeadweightlossofataxParetoefficiencyOutlineMarketEquilibrium271.MarketEquilibriumpD(p),S(p)q=D(p)Market

demandMarket

supplyq=S(p)p*q*1.MarketEquilibriumpD(p),S(28MarketEquilibriumAnexampleofcalculatingamarketequilibriumwhenthemarketdemandandsupplycurvesarelinear.MarketEquilibriumAnexampleo29MarketEquilibriumAttheequilibriumpricep*,D(p*)=S(p*).

Thatis,whichgivesandMarketEquilibriumAttheequil30MarketEquilibriumCanwecalculatethemarketequilibriumusingtheinversemarketdemandandsupplycurves?Yes,itisthesamecalculation.MarketEquilibriumCanwecalcu31MarketEquilibriumtheequationoftheinversemarket

demandcurve.Andtheequationoftheinversemarket

supplycurve.MarketEquilibriumtheequation32MarketEquilibriumandAttheequilibriumquantityq*,D-1(p*)=S-1(p*).

Thatis,whichgivesandMarketEquilibriumandAttheeq33QPp*Q*DemandcurveSupplycurvePQQ*p*SupplycurveDemandcurveAB2.SpecialcasesQPp*Q*DemandcurveSupplycurve34Specialcasesverticalsupply—quantitydeterminedbysupply,pricedeterminedbydemandhorizontalsupply—quantitydeterminedbydemand,pricedeterminedbysupplySpecialcasesverticalsupply—353.TheimpositionofaTaxLetPr

bethepricereceivedbyproducers

Pp

bethepricepaidbyconsumersTheproducerspaythequantitytaxPp=Pr+tTheconsumerspaythequantitytaxPp–t=Pr3.TheimpositionofaTaxLe36TheimpositionofaTaxTheimpositionofaTax37PassingalongthetaxSpecialcasesPassingalongthetaxSpecialc38DeadweightLosspD(p),S(p)Market

demandMarket

supplyp*q*NotaxCSPSDeadweightLosspD(p),S(p)Mark39DeadweightLosspD(p),S(p)Market

demandMarket

supplyp*q*$tppqtprCSPSTaxDeadweightlossDeadweightLosspD(p),S(p)Mark40DeadweightLossandElasticitiespD(p),S(p)Market

demandMarket

supplyp*q*$tpbqtpsDeadweightlossDeadweightLossandElasticiti41DeadweightLossandElasticitiespD(p),S(p)Market

demandMarket

supplyp*q*$tpbqtpsDeadweightlossfallsasmarketdemandbecomeslessown-priceelastic.DeadweightLossandElasticiti42DeadweightLossandElasticitiespD(p),S(p)Market

demandMarket

supplyps=p*$tpbqt=q*WheneD=0,thetaxcausesnodeadweightloss.DeadweightLossandElasticiti43