第7章成本分析萨缪尔逊经济学第十八版微观经济学

本钱分析第7章1本钱的经济分析7.12短期Theshortrun:Theperiodinwhichfirmscanadjustproductiononlybychangingvariablefactorssuchasmaterialsandlaborbutcannotchangefixedfactorssuchascapital.3固定本钱Thecostrelatedtofixedfactorsiscalledfixedcost(固定本钱，不变本钱).Afirm’sfixedcosts,sometimescalled“overhead〞(企业普通管理费用)or“sunkcosts〞(沉入本钱),mustbepaidevenifthefirmproducesnooutput,andtheywillnotchangeifoutputchanges.4变动本钱Thecostrelatedtovariablefactorsiscalledvariablecost(变动本钱，可变本钱).Variablecostsarethosewhichvaryasoutputchanges.Bydefinition,VCbeginsatzerowhenqiszero.5总本钱是可到达的最小本钱Totalcostrepresentsthelowesttotaldollarexpenseneededtoproduceeachlevelofoutputq.阐明：与消费函数的处置类似，总本钱也是指给定产量时的最小本钱，目的是为了让函数关系具有独一性。6Totalcostinshortrun:inlongrun:TotalcostVariablecost=FixedcostVariablecost+7(1)(2)(3)(4)QuantityFixedcostVariablecostTotalcost=(2)+(3)qFC($)VC($)TC($)055055155308525555110355751304551051605551552106552252808边沿本钱Theconceptofmarginalcostisoneofthemostessentialinmicroeconomics.Marginalcost(MC)denotestheextraoradditionalcostofproducing1extraunitofoutput.9Foranairlineflyingplaneswithemptyseats,theaddedcostofanotherpassengerisquitelow.Butonahotsummerday,wheneveryone’sconditionersarerunning,theaddedelectricpowercomesatahighmarginalcost.10边沿本钱的计算(1)(2)(3)OutputTotalcostMarginalcostQTC($)MC($)0551852110313041605210302520305011利用变动本钱计算边沿本钱(1)(2)(3)OutputVariablecostMarginalcostQVC($)MC($)0013025537541055155302520305012MC=TCq+1－TCq=(VCq+1＋FC)－(VCq＋FC)=VCq+1－VCq数学推导为什么可以用变动本钱来计算边沿本钱：13总本钱和边沿本钱的关系OutputTotalcostOutputMarginalcost14平均本钱Averagecost(orunitcost)=totalcostoutput=TCq=ACAveragefixedcost=fixedcostoutput=FCq=AFCAveragevariablecost=variablecostoutput=VCq=AVC15总本钱、固定本钱和变动本钱TotalcostVariablecostFixedcostQuantityCost16平均本钱和边沿本钱QuantityAverageandmarginalcostMCACAVCAFC平均本钱最小平均变动本钱最小17平均本钱与边沿本钱的关系本钱产量边沿本钱平均本钱平均本钱最低点边沿本钱曲线自下而上穿越平均本钱曲线的最低点。18平均本钱>边沿本钱本钱产量边沿本钱平均本钱边沿本钱＜平均本钱,平均本钱随着产量添加而向下。16元2212元19平均本钱<边沿本钱本钱产量边沿本钱平均本钱17元边沿本钱＞平均本钱,平均本钱随着产量添加而向上。23元5020边沿本钱和平均本钱的关系ACq+1=ACq×q＋MCq＋1=ACq×(q＋1)＋MC－ACqq＋1=ACq＋MC－ACqq＋121小结IfMC>AC,thenACisrising.IfMC=AC,thenACisatitslowpoint.IfMC<AC,thenACisfalling.QuantityACandMC=ACq＋MC－ACqq＋1ACq+1AC22边沿本钱和平均变动本钱的关系AVCq+1=AVCq×q＋MCq＋1=AVCq×(q＋1)＋MC－AVCqq＋1=AVCq＋MC－AVCqq＋123小结IfMC>AVC,thenAVCisrising.IfMC=AVC,thenAVCisatitslowpoint.IfMC<AVC,thenAVCisfalling.QuantityACandMC=AVCq＋MC－AVCqq＋1AVCq+1AVC24斜率和边沿本钱的关系TangentlineTotalcostcurve1unitofoutputMarginalcosta25产量与本钱之间的联络Thecostcurveforafirmdependsverycloselyon①thepricesofinputsand②thefirm’sproductionfunction.Ifyouknowfactorpricesandtheproductionfunction,youcancalculatethecostcurve.26(1)(2)(3)(4)(5)(6)OutputLandLaborRentWageTotalcost(tons)(acres)(workers)($/acre)($/worker)($)01005.555511065.55?210115.55110310155.55130410215.55160510315.55?610455.55280710635.55370810855.554808521027报酬递减和U形本钱曲线LaborMarginalproductoflaborMarginalcostOutputABDABDMCACIntheshortrun:28最小本钱规那么Toagivenoutput:MarginalproductofinputAPriceofinputA=MarginalproductofinputBPriceofinputB=……29等边沿原理Thisgivesyouthemarginalproductperdollarofoutput.EquimarginalPrinciple30替代规那么Ifthepriceofonefactorfallswhileallotherfactorpricesremainthesame,firmswillprofitbysubstitutingthenow-cheaperfactorforalltheotherfactors.MPofLaborPriceofLabor=MPofCapitalPriceofCapital31背景知识在资本主义由工场手工业向大机器消费过渡的历史时期，由于机器操作的简单性，女工、童工参与劳动行列，劳动供应添加。与此同时，大机器消费要求相对较多的资本，资本的供应相对稀缺。这是导致工人当时生活贫困的主要缘由。当资本不断积累，而消费又要求较为复杂的劳动技艺时，在要素市场上，资本不能够总是处于有利的竞争位置。32短期本钱与长期本钱的关系本钱产量长期平均本钱1亩地2亩地4亩地3亩地1亩地更有利2亩地更有利3亩地更有利4亩地更有利33规模经济与规模不经济本钱产量长期平均本钱规模经济规模不经济34经济本钱和企业会计7.235经济本钱和会计本钱经济本钱〔economiccost〕：投入消费的一切资源的时机本钱。会计本钱〔accountingcost〕：按照会计规那么计算的本钱在会计帐面上显示出来的经济本钱称为外显〔显性〕本钱〔explicitcosts〕，在会计帐面上不能显示出来的经济本钱称为内含〔隐性〕本钱〔implicitcosts〕。36经济利润经济本钱=外显本钱+内含本钱=时机本钱经济利润=销售收入–经济本钱经济利润是计入了一切运用的资源代价后的纯收益。37一个体饭馆业主运用本人的店面，1年盈利3万元，这个3万元称之为会计利润。假设不开饭馆，在一切可选任务中最高可赚得2万元，人力的经济本钱就是2万元。假设店面用于出租可以获得1.5万元租金，那么店面的经济本钱就是1.5万元。思索到经济本钱后，这个个体饭馆业主的经济利润为－0.5万元。38收益表(1)Netsales$250,000Lesscostofgoodssold:(2)Materials$50,000(3)Laborcost90,000(4)Miscellaneousoperatingcosts10,000(5)Lessoverheadcosts:(6)Sellingandadministrativecosts15,000(7)Rentforbuilding5,000(8)Depreciation15,000(9)Operatingexpenses$185,000185,000(10)Netoperatingincome$65,00039收益表(10)Netoperatingincome$65,000Less:(11)interestchargesonequipmentloan6,000(12)Stateandlocaltaxes4,000(13)Netincomebeforeincometaxes$55,000(14)Less:Corporationincometaxes18,000(15)Netincome(orprofit)aftertaxes$37,000(16)Less:Dividendspaidoncommonstock15,000(17)Additionorretainedearnings$22,00040Thedepreciationistakeninannualaccountingchargesovertheasset’saccountinglifetime折旧$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000∑depreciation=thecapitalgood’shistoricalcostorpurchaseprice.Depreciation=theannualcostofacapitalinputthatacompanyactuallyownsitself.41资产负债表AssetsLiabilitiesandnetworthLiabilitiesCurrentassets:Currentliabilities:Cash$20,000Accountspayable$20,000Inventory80,000Notespayable30,000Fixedassets:Long-termliabilities:Equipment150,000Bondspayable100,000Buildings100,000

NetworthStockholders’equity:________

Commonstock200,000Total$350,000Total$350,00042关于资产负债表Theincomestatementmeasurestheflowsintoandoutofthefirm,whilethebalancesheetmeasuresthestocksofassetsandliabilitiesattheendoftheaccountingyear.Abalancesheetmustalwaysbalance:Totalassets=totalliabilities+networth43例子Supposetotalassetsaredown$40,000;liabilitiesremainunchanged.Thismeanstotalnetworthhasdecreasedby$40,000,andshouldwritenetworthdownfromtheprevious$200,000toonly$160,000.AssetsLiabilitiesandnetworthLiabilities$40,000NetworthCommonstock$40,00044会计惯例Thevalueplacedonalmosteveryitemreflectsitshistoricalcosts.45阐明“收入表〞是描画一指定会计时间段中货币流入和流出企业的情况。“资产负债表〞是指在某一特定的会计时辰，企业的资产、负债和一切者权益情况。总之，“收入表〞是对一时段而言的，“资产负债表〞是对一时点而言的。46时机本钱7.347时机本钱Theopportunitycost(时机本钱)isthevalueofthegoodandserviceforgone(放弃).Theopportunitycostincludesallconsequences(结果),whethertheyreflectexplicitmonetarytransactions(货币买卖)ornot.48Theimmediatedollarcostofgoingtoamovieinsteadofreadingyoureconomicstextbookisthepriceofthemovieticket.Theopportunitycostalsoincludesthepossibilityofgainingabetterunderstandingofmicroeconomicsandthereforebecomingmoresuccessfulinbusiness.49问题WhydothestudentswatchmoreTVtheweekafterexamsthantheweekbeforeexams?50市场价钱与时机本钱在一个良好运转的市场上，价钱等于时机本钱。$25.02(Marketprice)$25.01(Opportunitycost)$24.9851消费、本钱实际和企业决策附录52消费函数的数值例子Q=1002LAQ=output;L=labor;A=land.Theproductionfunctionisaconstant-returns-to-scaleproductionfunction,aspecialcaseoftheCobb-Douglasproductionfunction.533464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456ConstantreturnstoscaleLaborLand543464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456DiminishingmarginalproductoflaborLaborLand8264544842553464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456DiminishingmarginalproductoflandLaborLand5258677710156给定产量的最低要素本钱组合(1)(2)(3)(4)InputCombinationTotalcostTotalcostLaborLandPL=$2PL=$2LAPA=$3PA=$1A1620?B2313?C3212?D6115?57给定产量的最低要素本钱组合(1)(2)(3)(4)InputCombinationTotalcostTotalcostLaborLandPL=$2PL=$2LAPA=$3PA=$1A162