管理经济学课件3

Demand,Supply,&MarketEquilibriumChenHongjunHenanUniversityofTechnologyChapter2

Demand,Supply,&MarketEq1MarketsandPricesWhydoesMingYAOearnmorethanChen(anawardwinningteacher)?MarketsandPricesWhydoesMin2MarketsandPricesWhydodiamondscostmorethanwater?MarketsandPricesWhydodiamo3MarketsandPricesWhydoQiBaiShi’s(齐白石)

crabssellformorethantherealones?MarketsandPricesWhydoQiBai4MarketsandPricesIsitcostofproductionthatdeterminesprices(asAdamSmiththought)?MarketsandPricesIsitcosto5MarketsandPricesOrisitwillingnesstopaythatdeterminesprices(asStanleyJevonsthought)?WilliamStanleyJevons(September1,1835-August13,1882),English

economistandlogician,wasborninLiverpool.MarketsandPricesOrisitwil6MarketsandPricesAlfredMarshall(PrinciplesofEconomics,1890)wasthefirsttoexplainclearlyhowbothcostsandwillingnesstopayinteracttodeterminemarketprices.MarketsandPricesAlfredMarsh7MarketsandPricesMarketsandPrices8WhatisaMarket?Amarketisanyarrangementthroughwhichbuyers&sellersexchangegoods&servicesMarketsreducetransactioncostsCostsofmakingatransactionotherthanthepriceofthegoodorserviceWhatisaMarket?Amarketisa9MarketStructuresMarketcharacteristicsthatdeterminetheeconomicenvironmentinwhichafirmoperatesNumber&sizeoffirmsinmarketDegreeofproductdifferentiationLikelihoodofnewfirmsenteringmarketMarketStructuresMarketcharac10PerfectCompetition

完全竞争LargenumberofrelativelysmallfirmsUndifferentiatedproductNobarrierstoentryPerfectCompetition

完全竞争Large11Monopoly完全垄断SinglefirmProducesproductwithnoclosesubstitutesProtectedbyabarriertoentry如电力、电话、自来水、天然气以及公共运输等行业。譬如，某人离家百米之内有一小杂货铺，油盐酱醋等日常生活用品一般在此购买。假定方圆10里之内只有这么一家卖油盐酱醋的小杂货铺，而一般推定人们往往不会为生活琐事舍近求远，因此，这家小杂货铺实际上无异于一个处于完全垄断地位的″垄断企业″。可以说小范围的完全垄断市场结构是经常存在的。Monopoly完全垄断Singlef12MonopolisticCompetition

垄断竞争LargenumberofrelativelysmallfirmsDifferentiatedproductsNobarrierstoentryMonopolisticCompetition

垄断竞争L13纳爱斯营养维C牙膏

选一支好牙膏，给自己加一份健康保障。云南白药牙膏，国家保密配方。”

冷热酸甜，想吃就吃

纳爱斯营养维C牙膏选一支好牙膏，给自己加一份健康保障。云南14Oligopoly

寡头垄断FewfirmsproduceallormostofmarketoutputProfitsareinterdependentActionsbyanyonefirmwillaffectsales&profitsoftheotherfirms如美国汽车业的通用、福特和克莱斯勒，投资银行业的美林、高盛和摩根斯坦利等Oligopoly

寡头垄断Fewf15DemandQuantitydemanded(Qd)Amountofagoodorserviceconsumersarewilling&abletopurchaseduringagivenperiodoftimeDemandQuantitydemanded(Qd)16DemandSixvariablesthatinfluenceQdPriceofgoodorservice(P)Incomesofconsumers(M.normal,inferior)Pricesofrelatedgoods&services(PR.)(substitutesandcomplements)Expectedfuturepriceofproduct(Pe)Numberofconsumersinmarket(N)Someexamplesofgoodsandservicesthatmightbeinferiorincludeshoerepairs,genericfoodproducts,andusedcars.DemandSixvariablesthatinflu17GeneralizedDemandFunctionb,c,d,e,f,&gareslopeparametersMeasureeffectonQd

ofchangingoneofthevariableswhileholdingtheothersconstantSignofparametershowshowvariableisrelatedtoQdPositivesignindicatesdirectrelationshipNegativesignindicatesinverserelationshipGeneralizedDemandFunction18GeneralizedDemandFunctionVariableRelationtoQdSignofSlopeParameterPPeNMPRInverseDirectDirectDirectDirectfornormalgoodsInverseforinferiorgoodsDirectforsubstitutesb=Qd/Pisnegativec=Qd/M

ispositivec=Qd/M

isnegatived=Qd/PR

ispositived=Qd/PR

isnegativef=Qd/Pe

ispositiveg=Qd/N

ispositiveInverseforcomplementse=Qd/

ispositiveGeneralizedDemandFunctionVar19DemandFunctionDemandfunction,ordemand,showsrelationbetweenP&Qd

whenallothervariablesareheldconstant

Qd=f(P)LawofDemandQd

increaseswhenPfalls&Qd

decreaseswhenPrises,allelseconstantQd/PmustbenegativeDemandFunctionDemandfunction20LawofDemand需求定律（TheLawofDemand）是说任何物品的价格下降，其需求量必定上升。古往今来，何时何地，不能有例外。这也是说，以竖线为价及竖线之下的横线为量，其中的需求曲线一定是向右下倾斜的。

需求定律是经济学的灵魂，其重要性是不能夸大的。任何经济学论著，有道之士可单看作者对这定律的操纵就知道作者的斤两如何。这定律不需要在文字上提到，但内容上这定律要墨守成规——我在自己的博士论文《佃农理论》上就刻意地完全不提“需求”，向老师表演一下。

--张五常《经济解释》之十七

LawofDemand需求定律（TheLawofD21张五常狂傲之魅

/u/11998399911935年生于香港，被誉为华人世界里最著名的经济学家，新制度经济学和现代产权经济学的创始人之一。

1982年起他担任香港大学经济金融学院教授、院长，他的理论主张往往在学术界引起广泛争议。主要著作有《佃农理论》（英文1969）、《社会成本的神话》（英文1978）、《中国会走向‘资本主义’的道路吗？》（英文1982）、《卖橘者言》（1984）等等。一方面，张五常教授在理论上下过苦功，“由浅入深、由深转复杂，再由复杂转深、再转浅，来来回回好几次”，已把价格理论咀嚼透烂。另一方面，张五常注重案例研究，大量时间用于现实问题的实践调查，多年砺炼，使他的学术素养和对现实问题的把握浑然一体。

他曾当选美国西部经济学会会长，是第一位获此职位的美国本土之外的学者。1969年以名为《佃农理论——引证于中国的农业及台湾的土地改革》的博士论文轰动西方经济学界。1991年作为唯一一位未获诺贝尔奖的经济学者而被邀请参加了当年的诺贝尔颁奖典礼。

张五常狂傲之魅

22GraphingDemandCurvesTraditionallyprice(P)isplottedontheverticalaxis&quantitydemanded(Qd)isplottedonthehorizontalaxisTheequationplottedistheinversedemandfunctionP=f(Qd)GraphingDemandCurvesTraditio23GraphingDemandCurvesApointonademandcurveshowseither:MaximumamountofagoodthatwillbepurchasedforagivenpriceMaximumpriceconsumerswillpayforaspecificamountofthegoodGraphingDemandCurvesApoint24GraphingDemandCurvesChangeinquantitydemandedOccurswhenpricechangesMovementalongdemandcurveChangeindemandOccurswhenoneoftheothervariables,ordeterminantsofdemand,changesDemandcurveshiftsrightward

orleftwardGraphingDemandCurvesChangei25ShiftsinDemand

(Figure2.2)Qd01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0D1D2••$50,300$50,600••$40,200$40,500DemandincreaseDemanddecreaseShiftsinDemand(Figure26SupplyQuantitysupplied(Qs)AmountofagoodorserviceofferedforsaleduringagivenperiodoftimeSupplyQuantitysupplied(Qs)27SupplySixvariablesthatinfluenceQsPriceofgoodorservice(P)Inputprices(PI)Pricesofgoodsrelatedinproduction(Pr)Technologicaladvances(T)Expectedfuturepriceofproduct(Pe)Numberoffirmsproducingproduct(F)Generalizedsupplyfunction

SupplySixvariablesthatinflu28GeneralizedSupplyFunctionk,l,m,n,r,&sareslopeparametersMeasureeffectonQs

ofchangingoneofthevariableswhileholdingtheothersconstantSignofparametershowshowvariableisrelatedtoQsPositivesignindicatesdirectrelationshipNegativesignindicatesinverserelationshipGeneralizedSupplyFunction29GeneralizedSupplyFunctionVariableRelationtoQsSignofSlopeParameterPPeFPIPrDirectDirectDirectInverseInverseInverseforsubstitutesk=Qs/Pispositivel=Qs/PI

isnegativem=Qs/Pr

isnegativem=Qs/Pr

ispositiver=Qs/Pe

isnegatives=Qs/F

ispositiveDirectforcomplementsn=Qs/T

ispositiveTGeneralizedSupplyFunctionVar30SupplyFunctionSupplyfunction,orsupply,showsrelationbetweenP&Qs

whenallothervariablesareheldconstant

Qs=g(P)SupplyFunctionSupplyfunction31GraphingSupplyCurvesApointonasupplycurveshowseither:MaximumamountofagoodthatwillbeofferedforsaleatagivenpriceMinimumpricenecessarytoinduceproducerstovoluntarilyofferaparticularquantityforsaleGraphingSupplyCurvesApoint32GraphingSupplyCurvesChangeinquantitysuppliedOccurswhenpricechangesMovementalongsupplycurveChangeinsupplyOccurswhenoneoftheothervariables,ordeterminantsofsupply,changesSupplycurveshiftsrightwardorleftwardGraphingSupplyCurvesChangei33S0S2S1SupplydecreaseQs07001009003005001020304050607080ShiftsinSupply

(Figure2.4)QuantityPrice(dollars)P$60,700$60,400••••$40,500$40,650SupplyincreaseS0S2S1SupplydecreaseQ34MarketEquilibriumEquilibriumprice&quantityaredeterminedbytheintersectionofdemand&supplycurvesAtthepointofintersection,Qd=QsConsumerscanpurchasealltheywant&producerscansellalltheywantatthe“market-clearing”priceMarketEquilibriumEquilibrium35S0MarketEquilibrium

(Figure2.5)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0•••••S0MarketEquilibrium(Figur36ThemarketforlobstersThemarketforlobstersinZhengzhou,onJanuary20,2009.ThemarketforlobstersThemar37MarketEquilibriumQuantityandPriceEquilibriumoccursattheprice-quantitypairforwhichbothbuyersandsellersaresatisfied.Atthemarketequilibriumpriceof$6perlobster,buyersandsellersareeachabletobuyorsellasmanylobstersastheywishto.MarketEquilibriumQuantityan38D2D1S0DemandShifts(SupplyConstant)

(Figure2.6)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0•••A•B•CD2D1S0DemandShifts(SupplyCo39DemandShiftsDemandShifts40S2S1S0SupplyShifts(DemandConstant)

(Figure2.7)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,3001020304050607080D0•••R•S•TS2S1S0SupplyShifts(DemandCo41SimultaneousShiftsWhendemand&supplyshiftsimultaneouslyCanpredicteitherthedirectioninwhichpricechangesorthedirectioninwhichquantitychanges,butnotboth

Thechangeinequilibriumpriceorquantityissaidtobeindeterminatewhenthedirectionofchangedependsontherelativemagnitudesbywhichdemand&supplyshiftSimultaneousShiftsWhendemand42AChangeinSupplyAChangeinSupply43SD’S’’S’DSimultaneousShifts:

(D,S)QPricemayriseorfall;QuantityrisesP•AQPB•P’Q’Q’’C•P’’SD’S’’S’DSimultaneousShifts:44DSimultaneousShifts:

(D,S)SD’S’’S’QPricefalls;QuantitymayriseorfallP•AQPB•P’Q’Q’’C•P’’DSimultaneousShifts:(D,S)45S’’SimultaneousShifts:

(D,S)DSD’S’QPricerises;QuantitymayriseorfallP•AQPB•P’Q’Q’’C•P’’S’’SimultaneousShifts:(D,46SimultaneousShifts:

(D,S)S’’DSD’S’QPricemayriseorfall;QuantityfallsP•AQPB•P’Q’Q’’C•P’’SimultaneousShifts:(D,S)S47管理经济学课件348Ceiling&FloorPricesQxQuantityPrice(dollars)QxPxPxQuantityPrice(dollars)SxDx2501622233284PanelA–CeilingpriceSxDx250PanelB–FloorpriceCeiling&FloorPricesQxQuant49Excesssupply(FloorPrices)A

situationinwhichpriceexceedsitsequilibriumvalueiscalledoneofexcesssupply,or

surplus.At$8,thereisanexcesssupplyof2000lobstersinthismarket.Excesssupply(FloorPrices)A50ExcessDemandAsituationinwhichpriceliesbelowitsequilibriumvalueisreferredtoasoneofexcessdemand.Atapriceof$4inthislobstermarket,thereisanexcessdemandof2000lobsters.ExcessDemandAsituationinwh51ZeroexcesssupplyanddemandEquilibriumoccursattheprice-quantitypairforwhichbothbuyersandsellersaresatisfied.Atthemarketequilibriumpriceof$6,bothexcessdemandandexcesssupplyareexactlyzero..ZeroexcesssupplyanddemandE52Example3.1.Atapriceof$2inthishypotheticallobstermarket,howmuchexcessdemandforlobsterswilltherebe?Howmuchexcesssupplywilltherebeatapriceof$10?DDSS123450246810Price($/lobster)Quantity(1000lobsters/day)Example3.1.Atapriceof$2i53TheTradingLocusWhenpricediffersfromtheequilibriumprice,tradinginthemarketplacewillbeconstrained--bythebehaviorofbuyersifthepriceliesaboveequilibrium,bythebehaviorofsellersifbelow.TradinglocusTheTradingLocusWhenpricedi54FromdisequilibriumtoequilibriumAtpricesaboveequilibrium,sellersarenotsellingasmuchastheywantto.Theimpulseofadissatisfiedselleristoreducehisprice.Fromdisequilibriumtoequilib55FromdisequilibriumtoequilibriumAtpricesbelowtheequilibriumvalue,buyerscannotobtainthequantitiestheywishtopurchase.Somebuyersadjustbyofferingslightlyhigherprices.Fromdisequilibriumtoequilib56FromdisequilibriumtoequilibriumAnextraordinaryfeatureofthisequilibratingprocessisthatnooneconsciouslyplansordirectsit.Theactualstepsthatconsumersandproducersmusttaketomovetowardequilibriumareoftenindescribablycomplex.Supplierslookingtoexpandtheiroperations,forexample,mustchoosefromabewilderinglylargemenuofequipmentoptions.Buyers,fortheirpart,faceliterallymillionsofchoicesabouthowtospendtheirmoney.Fromdisequilibriumtoequilib57FromdisequilibriumtoequilibriumAndyettheadjustmenttowardequilibriumresultsmoreorlessautomaticallyfromthenaturalreactionsofself-interestedindividualsfacingeithersurplusesorshortages.Fromdisequilibriumtoequilib58Ceiling&FloorPricesCeilingpriceMaximumpricegovernmentpermitssellerstochargeforagoodWhenceilingpriceisbelowequilibrium,ashortageoccursFloorpriceMinimumpricegovernmentpermitssellerstochargeforagoodWhenfloorpriceisaboveequilibrium,asurplusoccursCeiling&FloorPricesCeiling59昆明市民呼吁米线限价律师支持政府干预_县域经济_农博网给牛肉面限价一些“心理”支持这几天关于兰州牛肉面限价的新闻已是铺天盖地，争议声四起，广州日报7月1日的报道说：兰州市物价局副局长魏立中在通报会上表示：牛肉面价格就是兰州人心中的民生价格。

发表日期：2007年7月18日

潘石屹:限价房无法律支持

造成市场混乱

孙红丽2008年12月12日11:33

来源：人民网-房产频道化肥“限价令”遭遇执行尴尬

国家发改委近日发布的《当前化肥生产形势应予关注》报告称，为了维护农民利益，国家对化肥产品实行限价，但由于政府给予的化肥生产企业一些优惠政策如化肥用煤炭限价落实不到位等问题，导致企业经营生产困难，甚至亏损停产。该报告指出：“一旦化肥供给数量低于农业需求，影响到农业生产特别是粮食生产，将对粮食安全产生较大的负面影响。”并建议有关部门适时调整政策取向和调控力度，为化肥行业与农业的和谐发展创造条件。

在市场行为与限价政策杠杆的较量中，政策变得越来越“力不从心”，目前化肥市场正处于价格限又限不住、放又不敢放的尴尬局面。既然补贴农资生产环节难以监管，政府不妨借鉴给农民发放粮食直补的做法，将过去对流通环节的间接补贴改为对农民的直接补贴。

昆明市民呼吁米线限价律师支持政府干预_县域经济_农博网60Questions/CommentsThankyou!Questions/Comments61Demand,Supply,&MarketEquilibriumChenHongjunHenanUniversityofTechnologyChapter2

Demand,Supply,&MarketEq62MarketsandPricesWhydoesMingYAOearnmorethanChen(anawardwinningteacher)?MarketsandPricesWhydoesMin63MarketsandPricesWhydodiamondscostmorethanwater?MarketsandPricesWhydodiamo64MarketsandPricesWhydoQiBaiShi’s(齐白石)

crabssellformorethantherealones?MarketsandPricesWhydoQiBai65MarketsandPricesIsitcostofproductionthatdeterminesprices(asAdamSmiththought)?MarketsandPricesIsitcosto66MarketsandPricesOrisitwillingnesstopaythatdeterminesprices(asStanleyJevonsthought)?WilliamStanleyJevons(September1,1835-August13,1882),English

economistandlogician,wasborninLiverpool.MarketsandPricesOrisitwil67MarketsandPricesAlfredMarshall(PrinciplesofEconomics,1890)wasthefirsttoexplainclearlyhowbothcostsandwillingnesstopayinteracttodeterminemarketprices.MarketsandPricesAlfredMarsh68MarketsandPricesMarketsandPrices69WhatisaMarket?Amarketisanyarrangementthroughwhichbuyers&sellersexchangegoods&servicesMarketsreducetransactioncostsCostsofmakingatransactionotherthanthepriceofthegoodorserviceWhatisaMarket?Amarketisa70MarketStructuresMarketcharacteristicsthatdeterminetheeconomicenvironmentinwhichafirmoperatesNumber&sizeoffirmsinmarketDegreeofproductdifferentiationLikelihoodofnewfirmsenteringmarketMarketStructuresMarketcharac71PerfectCompetition

完全竞争LargenumberofrelativelysmallfirmsUndifferentiatedproductNobarrierstoentryPerfectCompetition

完全竞争Large72Monopoly完全垄断SinglefirmProducesproductwithnoclosesubstitutesProtectedbyabarriertoentry如电力、电话、自来水、天然气以及公共运输等行业。譬如，某人离家百米之内有一小杂货铺，油盐酱醋等日常生活用品一般在此购买。假定方圆10里之内只有这么一家卖油盐酱醋的小杂货铺，而一般推定人们往往不会为生活琐事舍近求远，因此，这家小杂货铺实际上无异于一个处于完全垄断地位的″垄断企业″。可以说小范围的完全垄断市场结构是经常存在的。Monopoly完全垄断Singlef73MonopolisticCompetition

垄断竞争LargenumberofrelativelysmallfirmsDifferentiatedproductsNobarrierstoentryMonopolisticCompetition

垄断竞争L74纳爱斯营养维C牙膏

选一支好牙膏，给自己加一份健康保障。云南白药牙膏，国家保密配方。”

冷热酸甜，想吃就吃

纳爱斯营养维C牙膏选一支好牙膏，给自己加一份健康保障。云南75Oligopoly

寡头垄断FewfirmsproduceallormostofmarketoutputProfitsareinterdependentActionsbyanyonefirmwillaffectsales&profitsoftheotherfirms如美国汽车业的通用、福特和克莱斯勒，投资银行业的美林、高盛和摩根斯坦利等Oligopoly

寡头垄断Fewf76DemandQuantitydemanded(Qd)Amountofagoodorserviceconsumersarewilling&abletopurchaseduringagivenperiodoftimeDemandQuantitydemanded(Qd)77DemandSixvariablesthatinfluenceQdPriceofgoodorservice(P)Incomesofconsumers(M.normal,inferior)Pricesofrelatedgoods&services(PR.)(substitutesandcomplements)Expectedfuturepriceofproduct(Pe)Numberofconsumersinmarket(N)Someexamplesofgoodsandservicesthatmightbeinferiorincludeshoerepairs,genericfoodproducts,andusedcars.DemandSixvariablesthatinflu78GeneralizedDemandFunctionb,c,d,e,f,&gareslopeparametersMeasureeffectonQd

ofchangingoneofthevariableswhileholdingtheothersconstantSignofparametershowshowvariableisrelatedtoQdPositivesignindicatesdirectrelationshipNegativesignindicatesinverserelationshipGeneralizedDemandFunction79GeneralizedDemandFunctionVariableRelationtoQdSignofSlopeParameterPPeNMPRInverseDirectDirectDirectDirectfornormalgoodsInverseforinferiorgoodsDirectforsubstitutesb=Qd/Pisnegativec=Qd/M

ispositivec=Qd/M

isnegatived=Qd/PR

ispositived=Qd/PR

isnegativef=Qd/Pe

ispositiveg=Qd/N

ispositiveInverseforcomplementse=Qd/

ispositiveGeneralizedDemandFunctionVar80DemandFunctionDemandfunction,ordemand,showsrelationbetweenP&Qd

whenallothervariablesareheldconstant

Qd=f(P)LawofDemandQd

increaseswhenPfalls&Qd

decreaseswhenPrises,allelseconstantQd/PmustbenegativeDemandFunctionDemandfunction81LawofDemand需求定律（TheLawofDemand）是说任何物品的价格下降，其需求量必定上升。古往今来，何时何地，不能有例外。这也是说，以竖线为价及竖线之下的横线为量，其中的需求曲线一定是向右下倾斜的。

需求定律是经济学的灵魂，其重要性是不能夸大的。任何经济学论著，有道之士可单看作者对这定律的操纵就知道作者的斤两如何。这定律不需要在文字上提到，但内容上这定律要墨守成规——我在自己的博士论文《佃农理论》上就刻意地完全不提“需求”，向老师表演一下。

--张五常《经济解释》之十七

LawofDemand需求定律（TheLawofD82张五常狂傲之魅

/u/11998399911935年生于香港，被誉为华人世界里最著名的经济学家，新制度经济学和现代产权经济学的创始人之一。

1982年起他担任香港大学经济金融学院教授、院长，他的理论主张往往在学术界引起广泛争议。主要著作有《佃农理论》（英文1969）、《社会成本的神话》（英文1978）、《中国会走向‘资本主义’的道路吗？》（英文1982）、《卖橘者言》（1984）等等。一方面，张五常教授在理论上下过苦功，“由浅入深、由深转复杂，再由复杂转深、再转浅，来来回回好几次”，已把价格理论咀嚼透烂。另一方面，张五常注重案例研究，大量时间用于现实问题的实践调查，多年砺炼，使他的学术素养和对现实问题的把握浑然一体。

他曾当选美国西部经济学会会长，是第一位获此职位的美国本土之外的学者。1969年以名为《佃农理论——引证于中国的农业及台湾的土地改革》的博士论文轰动西方经济学界。1991年作为唯一一位未获诺贝尔奖的经济学者而被邀请参加了当年的诺贝尔颁奖典礼。

张五常狂傲之魅

83GraphingDemandCurvesTraditionallyprice(P)isplottedontheverticalaxis&quantitydemanded(Qd)isplottedonthehorizontalaxisTheequationplottedistheinversedemandfunctionP=f(Qd)GraphingDemandCurvesTraditio84GraphingDemandCurvesApointonademandcurveshowseither:MaximumamountofagoodthatwillbepurchasedforagivenpriceMaximumpriceconsumerswillpayforaspecificamountofthegoodGraphingDemandCurvesApoint85GraphingDemandCurvesChangeinquantitydemandedOccurswhenpricechangesMovementalongdemandcurveChangeindemandOccurswhenoneoftheothervariables,ordeterminantsofdemand,changesDemandcurveshiftsrightward

orleftwardGraphingDemandCurvesChangei86ShiftsinDemand

(Figure2.2)Qd01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0D1D2••$50,300$50,600••$40,200$40,500DemandincreaseDemanddecreaseShiftsinDemand(Figure87SupplyQuantitysupplied(Qs)AmountofagoodorserviceofferedforsaleduringagivenperiodoftimeSupplyQuantitysupplied(Qs)88SupplySixvariablesthatinfluenceQsPriceofgoodorservice(P)Inputprices(PI)Pricesofgoodsrelatedinproduction(Pr)Technologicaladvances(T)Expectedfuturepriceofproduct(Pe)Numberoffirmsproducingproduct(F)Generalizedsupplyfunction

SupplySixvariablesthatinflu89GeneralizedSupplyFunctionk,l,m,n,r,&sareslopeparametersMeasureeffectonQs

ofchangingoneofthevariableswhileholdingtheothersconstantSignofparametershowshowvariableisrelatedtoQsPositivesignindicatesdirectrelationshipNegativesignindicatesinverserelationshipGeneralizedSupplyFunction90GeneralizedSupplyFunctionVariableRelationtoQsSignofSlopeParameterPPeFPIPrDirectDirectDirectInverseInverseInverseforsubstitutesk=Qs/Pispositivel=Qs/PI

isnegativem=Qs/Pr

isnegativem=Qs/Pr

ispositiver=Qs/Pe

isnegatives=Qs/F

ispositiveDirectforcomplementsn=Qs/T

ispositiveTGeneralizedSupplyFunctionVar91SupplyFunctionSupplyfunction,orsupply,showsrelationbetweenP&Qs

whenallothervariablesareheldconstant

Qs=g(P)SupplyFunctionSupplyfunction92GraphingSupplyCurvesApointonasupplycurveshowseither:MaximumamountofagoodthatwillbeofferedforsaleatagivenpriceMinimumpricenecessarytoinduceproducerstovoluntarilyofferaparticularquantityforsaleGraphingSupplyCurvesApoint93GraphingSupplyCurvesChangeinquantitysuppliedOccurswhenpricechangesMovementalongsupplycurveChangeinsupplyOccurswhenoneoftheothervariables,ordeterminantsofsupply,changesSupplycurveshiftsrightwardorleftwardGraphingSupplyCurvesChangei94S0S2S1SupplydecreaseQs07001009003005001020304050607080ShiftsinSupply

(Figure2.4)QuantityPrice(dollars)P$60,700$60,400••••$40,500$40,650SupplyincreaseS0S2S1SupplydecreaseQ95MarketEquilibriumEquilibriumprice&quantityaredeterminedbytheintersectionofdemand&supplycurvesAtthepointofintersection,Qd=QsConsumerscanpurchasealltheywant&producerscansellalltheywantatthe“market-clearing”priceMarketEquilibriumEquilibrium96S0MarketEquilibrium

(Figure2.5)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0•••••S0MarketEquilibrium(Figur97ThemarketforlobstersThemarketforlobstersinZhengzhou,onJanuary20,2009.ThemarketforlobstersThemar98MarketEquilibriumQuantityandPriceEquilibriumoccursattheprice-quantitypairforwhichbothbuyersandsellersaresatisfied.Atthemarketequilibriumpriceof$6perlobster,buyersandsellersareeachabletobuyorsellasmanylobstersastheywishto.MarketEquilibriumQuantityan99D2D1S0DemandShifts(SupplyConstant)

(Figure2.6)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,5001,3001020304050607080D0•••A•B•CD2D1S0DemandShifts(SupplyCo100DemandShiftsDemandShifts101S2S1S0SupplyShifts(DemandConstant)

(Figure2.7)Qd,Qs01,100700100QuantityPrice(dollars)900P3005001,3001020304050607080D0•••R•S•TS2S1S0SupplyShifts(DemandCo102SimultaneousShiftsWhendemand&supplyshiftsimultaneouslyCanpredicteitherthedirectioninwhichpricechangesorthedirectioninwhichquantitychanges,butnotboth

Thechangeinequilibriumpriceorquantityissaidtobeindeterminatewhenthedirectionofchangedependsontherelativemagnitudesbywhichdemand&supplyshiftSimultaneousShiftsWhendemand103AChangeinSupplyAChangeinSupply104SD’S’’S’DSimultaneousShifts:

(D,S)QPricemayriseorfall;QuantityrisesP•AQPB•P’Q’Q’’C•P’’SD’S’’S’DSimultaneousShifts:105DSimultaneousShifts:

(D,S)SD’S’’S’QPricefalls;QuantitymayriseorfallP•AQPB•P’Q’Q’’C•P’’DSimultaneousShifts:(D,S)106S’’SimultaneousShifts:

(D,S)DSD’S’QPricerises;QuantitymayriseorfallP•AQPB•P’Q’Q’’C•P’’S’’SimultaneousShifts:(D,107SimultaneousShifts:

(D,S)S’’DSD’S’QPricemayriseorfall;QuantityfallsP•AQPB•P’Q’Q’’C•P’’SimultaneousShifts:(D,S)S108管理经济学课件3109Ceiling&FloorPricesQxQuantityPrice(dollars)QxPxPxQuantityPrice(dollars)SxDx2501622233284PanelA–CeilingpriceSxDx250PanelB–FloorpriceCeiling&FloorPricesQxQuant110Excesssupply(FloorPrices)A

situationinwhichpriceexceedsitsequilibriumvalueiscalledoneofexcesssupply,or

surplus.At$8,thereisanexcesssupplyof2000lobstersinthismarket.Excesssupply(FloorPrices)A111ExcessDemandAsituationinwhichpriceliesbelowitsequilibriumvalueisreferredtoasoneofexcessdemand.Atapriceof$4inthislobstermarket,thereisanexcessdemandof2000lobsters.ExcessDemandAsituationinwh112ZeroexcesssupplyanddemandEquilibriumoccursattheprice-quantitypairforwhichbothbuyersandsellersare