ch02需求、供给和均衡价格.ppt

Ch02Overviewofthedemandsupplyandthebasicconcepts,Section1Section2Section3Section4Section5Section6Section7Section8,MicroeconomicscharacteristicDemandCurve.SupplyCurve.InteractionofDemandwithSupplyEconomicmodel,static,comparativestaticanddynamicanalysisDemand厂商：利润最大化;政府：社会福利最大化.,第一节微观经济学的特点,三、对微观经济学的鸟瞰,四、微观经济学的内容框架,供求均衡,需求弹性,供给弹性,消费行为,一般均衡和福利理论,生产要素价格,生产要素组合,厂商均衡,供求（效用）理论,生产（成本）理论,市场（厂商）理论,分配理论,微观经济政策,供求理论,消费理论,厂商理论,基数效用理论,序数效用理论,生产理论,成本理论,产品市场理论,完全竞争,垄断竞争,寡头垄断,完全垄断,要素市场理论,工资理论,地租理论,利息理论,利润理论,一般均衡理论,五、TheorySystemofMicro-economics微观经济学理论体系,弹性理论,博弈论,价格理论,微观经济政策,局部均衡,局部均衡,局部均衡,局部均衡,六、微观经济学课程结构,一、价格理论供、求（第二章）二、求的分析消费者行为（第三章）三、供的分析生产者行为（第四七章）1.生产技术分析：不考虑成本问题（第四章）2.成本分析：（第五章）3.市场分析：完全竞争、不完全竞争（第六、七章）四、分配问题（第八章）五、一般均衡与福利经济学（第九章）六、博弈论（第十章）七、市场失灵与政府干预（第十一章）,2.1demand&quantitydemanded需求与需求量,Section2demandcurve,Tofocusourthinking,letskeepinmindaparticulargoodicecream.以冰激凌为例,2.2Thefunctionofdemand需求函数,2.3DemandSchedule&DemandCurve需求表与需求曲线,2.4MarketDemand市场需求,2.5ChangeinQuantityDemandedversusChangeinDemand需求量的改变与需求改变,CASESTUDY:TWOWAYSTOREDUCETHEQUANTITYOFSMOKINGDEMANDED减少香烟需求量的两种方法,2.1demand&quantitydemanded,Ifyoudemandsomething,thenyou(1)Wantit,需要(2)Canaffordit,能负担(3)Havemadeadefiniteplantobuyit.购买计划,Demandistheamountofagoodthatbuyersarewillingandabletopurchaseatanypriceinaspecialperiod.消费者在一定的时期内、在各种可能的价格水平上愿意并且能够购买商品的数量。,2.1.1Theconceptsofdemand&quantitydemanded需求与需求量的概念,2.1demand&quantitydemanded,Thequantitydemandedofagoodorserviceistheamountthatconsumersplantobuyduringaparticulartimeperiod,andataparticularprice.需求量是指消费者在一定的时期内、在特定的价格水平上愿意并且能够购买商品的数量。,Wantsaretheunlimiteddesiresorwishespeoplehaveforgoodsandservices.Demandreflectsadecisionaboutwhichwantstosatisfy.需要是指人们对商品和服务天然的渴望；需求既反映愿望也反映购买能力。,2.1.1Theconceptsofdemand&quantitydemanded,2.1.2LawofDemand,thelawofdemand（需求法则）:Otherthingsequal,Whenthepriceofagoodrises,thequantitydemandedofthegoodfalls.一般说来，在其他条件不变的的情况下，当某种商品的价格上升时，其需求量下降。Thelawofdemandstatesthatthereisaninverserelationshipbetweenpriceandquantitydemanded.需求法则表示商品的需求量和价格之间呈反向变动关系。,2.1demand&quantitydemanded,Sixmainfactorsthatchangedemandare影响需求的六大主要因素:(1)Income收入(2)Thepricesofrelatedgoods相关商品的价格(3)Expectedfutureprices价格预期(4)Expectedfutureincome收入预期(5)Population人口(6)Preferences偏好,2.1.3DeterminantsofDemand需求的决定,Income消费者的收入水平,Whatwouldhappentoyourdemandforicecreamifyougotanincreaseinincome?如果收入增加了，你对冰激凌的需求会变吗？,eg.Tobuyacarortoridethebus?,正常商品是指收入增加，需求增加的商品。,低档商品是指收入增加，需求下降的商品。,PricesofRelatedGoods,Whatwouldhappentoyourdemandforicecreamifthepriceoffrozenyogurt（冻酸奶）wentup?,Asubstituteisagoodthatcanbeusedinplaceofanothergood.eg.icecreamandfrozenyogurt,Acomplementisagoodthatisusedinconjunctionwithanothergood.eg.icecreamandhotfudge热奶油,独立满足同一需要。,共同满足某一需要。,替代品,互补品,Preferences(Tastes),Themostobviousdeterminantofyourdemandisyourtastes.Ifyoulikeicecream,youbuymoreofit.Economistsnormallydonottrytoexplainpeoplestastesbecausetastesarebasedonhistoricalandpsychologicalforcesthatarebeyondtherealmofeconomics.Economistsdo,however,examinewhathappenswhentasteschange.影响需求最显著的因素是偏好，如果你偏好冰激凌，你就会买更多。但因为基于传统和心理因素的偏好超出经济学研究范围，经济学家不解释偏好的产生，只考虑偏好发生变化对需求的影响。,Peoplewiththesameincomehavedifferentdemandsiftheyhavedifferentpreferences.,ExpectedFuturePrices,Ifthepriceofagoodisexpectedtoriseinthefuture,currentdemandforthegoodincreases.如果预期某种商品将来涨价，其当前需求量就会增加。,Whatwouldhappentoyourtodaysdemandforicecreamifyouexpectthepriceoficecreamtorisetomorrow?如果预期明天冰淇淋涨价，今天冰淇淋的需求量会怎样变化？youmaybemorewillingtospendsomeofyourcurrentsavingsbuyingicecream.,ExpectedFutureIncome,Whenincomeisexpectedtoincreaseinthefuture,thedemandmightincreasenow.如果预期将来收入会增加，当前需求量就会增加,Whatwouldhappentoyourdemandforicecreamifyouexpecttoearnahigherincomenextmonth?如果你预期下月收入增加，冰淇淋的需求量会怎样变化？youmaybemorewillingtospendsomeofyourcurrentsavingsbuyingicecream.,Populationandothers,Thelargerthepopulation,thegreateristhedemandforallgoods.,除此之外，还有收入分配、气候、消费者规模和结构、广告宣传、政府政策、时间等因素也可能会影响商品的需求。价格和收入主要影响购买能力；消费者的偏好和预期主要影响购买欲望。,需求函数,影响需求的因素,需求影响因素与需求量的关系,消费者的偏好,f(P,PS,PC,Y,T),2.2Thefunctionofdemand,用来表示一种商品的需求数量和影响该需求数量的各种因素之间关系的函数，叫需求函数。用公式表示为：,Qdx=f(PX,Y,PY,U,Ye,Pe).广义需求函数如果其他因素不变，则商品自身价格与需求量的关系为：Qdx=f(PX).侠义需求函数用一元一次线性函数表示为：Qx=abPx或如：Qx=800100Px非线性需求函数,Q=-P,d,d,d,2.2Thefunctionofdemand,2.3DemandSchedule&DemandCurve,Thedemandscheduleisatablethatshowstherelationshipbetweenthepriceofthegoodandthequantitydemanded.需求表：需求量和价格之间关系表。,2.3.1DemandSchedule,Table2-1liusdemandschedule,$3.00,2.50,2.00,1.50,1.00,0.50,2,1,3,4,5,6,7,8,9,10,12,11,PriceofIce-CreamCone,QuantityofIce-CreamCones,0,2.3.2DemandCurve,Thedemandcurveisthedownward-slopinglinerelatingpricetoquantitydemanded.需求曲线是一条表示价格与需求量之间关系、从左上方向右下方倾斜的曲线。,CeterisParibus其他条件不变,CeterisparibusisaLatinphrasethatmeansallvariablesotherthantheonesbeingstudiedareassumedtobeconstant.Literally,ceterisparibusmeans“otherthingsbeingequal.”,Thedemandcurveslopesdownwardbecause,ceterisparibus,lowerpricesimplyagreaterquantitydemanded!,2.4MarketDemand,Marketdemand市场需求referstothesumofallindividualdemandsforaparticulargoodorservice.指具体商品的全部个体需求的总和。Graphically,individualdemandcurvesaresummedhorizontallytoobtainthemarketdemandcurve.从几何图形上，个体需求曲线横向叠加就能得到市场需求曲线。,2.4MarketDemand,Table2-2showsthedemandschedulesforicecreamoftwoindividuals-LiuandLiatanyprice,Themarketdemandisthesumofthetwoindividualdemands.表2-2表示刘和李两个个体对冰淇淋的需求表，市场需求为个人需求之和。,Table2-2IndividualandMarketDemandSchedule,2.4MarketDemand,LiusdemandLisdemand=Marketdemand,Figure2-2