北大中级微观经济学课件ch.ppt

ChapterNine BuyingandSelling购买和销售 Structure Endowments 禀赋 BudgetconstraintswithendowmentsNetdemandsPriceoffercurveExample LaborsupplyComparativestaticsSlutskyequationrevisited BuyingandSelling Tradeinvolvesexchange whensomethingisboughtsomethingelsemustbesold Whatwillbebought Whatwillbesold Whowillbeabuyer Whowillbeaseller BuyingandSelling Andhowareincomesgenerated Howdoesthevalueofincomedependuponcommodityprices Howcanweputallthistogethertoexplainbetterhowpricechangesaffectdemands Endowments Thelistofresourceunitswithwhichaconsumerstartsishisendowment 禀赋 Aconsumer sendowmentwillbedenotedbythevector omega Endowments E g statesthattheconsumerisendowedwith10unitsofgood1and2unitsofgood2 Whatistheendowment svalue Forwhichconsumptionbundlesmayitbeexchanged Endowments p1 2andp2 3sothevalueoftheendowmentisQ Forwhichconsumptionbundlesmaytheendowmentbeexchanged A Foranybundlecostingnomorethantheendowment svalue BudgetConstraintsRevisited So givenp1andp2 thebudgetconstraintforaconsumerwithanendowmentisThebudgetsetis BudgetConstraintsRevisited x2 x1 w1 w2 BudgetConstraintsRevisited x2 x1 w1 w2 Budgetset ChangingEndowments x2 x1 w1 w2 w1 w2 w1 w2 Changingtheendowment ChangingPrices x2 x1 w1 w2 Changingpricesoftheendowment ChangingPrices x2 x1 w1 w2 Budgetset ChangingPrices x2 x1 w1 w2 Theendowmentpointisalwaysonthebudgetconstraint Sopricechangespivottheconstraintabouttheendowmentpoint NetDemand TheconstraintisThatis thesumofthevaluesofaconsumer snetdemands 净需求 iszero NetDemands Supposeandp1 2 p2 3 ThentheconstraintisIftheconsumergrossdemands 毛需求 x1 x2 7 4 then3good1unitsexchangefor2good2units Netdemandsarex1 w1 7 10 3andx2 w2 4 2 2 NetDemands p1 2 p2 3 x1 w1 3andx2 w2 2so Thepurchaseof2extragood2unitsat 3eachisfundedbygivingup3good1unitsat 2each NetDemandsatDifferentPrices x2 x1 w1 w2 x2 x1 Atprices p1 p2 theconsumersellsunitsofgood1toacquiremoreunitsofgood2 Netsellerofgood1 x2 x1 w1 w2 x2 x1 Atprices p1 p2 theconsumersellsunitsofgood2toacquiremoreofgood1 Netbuyerofgood1 NetDemandsatDifferentPrices x2 x1 x2 w2 x1 w1 Atprices p1 p2 theconsumerconsumesherendowment netdemandsareallzero Autarky NetDemandsatDifferentPrices OfferCurve x2 x1 w1 w2 Price offercurvecontainsalltheutility maximizinggrossdemandsforwhichtheendowmentcanbeexchanged NetDemands x2 x1 w1 w2 Price offercurve Sellgood1 buygood2 NetDemands x2 x1 w1 w2 Price offercurve Buygood1 sellgood2 因课件太大 无法上传 本处删除了2张关于提供曲线和需求曲线的几何图形的图片格式 请看教材图形 cym SomeResultsaboutPriceChange Ifaconsumerisanetsellerofagood whenthepriceofthegooddecreases ifsheremainsabuyerthentheconsumerisworseoff Ifaconsumerifanetbuyerofagood whenthepricedecreases theconsumerwillremainabuyerandbebetteroff 因课件太大 无法上传 本处删除了2张关于价格变动 商品1价格下降 上升 的几何图形的图片格式 请看教材图形 cym LaborSupply Aworkerisendowedwith mofnonlaborincomeandRhoursoftimewhichcanbeusedforlabororleisure w R m Consumptiongood spriceispc wisthewagerate LaborSupply Theworker sbudgetconstraintiswhereC Rdenotegrossdemandsfortheconsumptiongoodandforleisure Thatis endowmentvalue expenditure LaborSupply rearrangesto LaborSupply C R R endowment m LaborSupply C R R endowment m LaborSupply C R R endowment m LaborSupply C R R endowment m slope the realwagerate LaborSupply C R R endowment m C R leisuredemanded laborsupplied LaborSupplyCurve Slutsky sEquationRevisited Slutsky changestodemandscausedbyapricechangearethesumofapuresubstitutioneffect andanincomeeffect Thisassumedthatincomeydidnotchangeaspriceschanged Butdoeschangewithprice HowdoesthismodifySlutsky sequation Slutsky sEquationRevisited Achangeinp1orp2changessotherewillbeanadditionalincomeeffect calledtheendowmentincomeeffect 禀赋收入效应 Slutsky sdecompositionwillthushavethreecomponentsapuresubstitutioneffectan ordinary incomeeffect andanendowmentincomeeffect Slutsky sEquationRevisited x1 w2 w1 x2 x2 x1 Initialpricesare p1 p2 Slutsky sEquationRevisited x1 w2 w1 x2 x2 x1 x2 Initialpricesare p1 p2 Finalpricesare p1 p2 x1 Slutsky sEquationRevisited x1 w2 w1 x2 x2 x1 x2 Initialpricesare p1 p2 Finalpricesare p1 p2 Howisthechangeindemandfrom x1 x2 to x1 x2 explained x1 Slutsky sEquationRevisited x1 w2 w1 x2 x2 x1 Initialpricesare p1 p2 Slutsky sEquationRevisited x1 w2 w1 x2 x2 x1 x2 Initialpricesare p1 p2 Finalpricesare p1 p2 x1 Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutioneffect Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutioneffect Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutioneffect Ordinaryincomeeffect Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutioneffect Ordinaryincomeeffect Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutioneffect Ordinaryincomeeffect Endowmentincomeeffect Slutsky sEquationRevisited x1 w2 w1 x2 Puresubstitutio