微观经济学chapter 7 -更新版

Chapter7

AnalysisofCosts

黄新飞

InternationalBusinessSchoolSun－YatSenUniversity编辑ppt中国案例分析1：非典啊非典型经济学关于非典的问题：其一，口罩价格暴涨，但大众对口罩的需求量仍然大增，这有违反需求定律吗？其二，假设非典之前的口罩价格是1元，非典发生后涨价为10元，为什么会出现这样的现象？也就是说，为什么口罩供应商的库存是以1元购进的，现在却以10元出售？其三，如果政府受舆论影响而出台行政命令禁止口罩供应商涨价，会有什么结果？2编辑ppt 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVC 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 7 18 50 157 207 2.78 8.72 11.50 21 50 182 232 2.38 8.67 11.05 23 50 200 250 2.17 8.70 10.87 10 24 50 210 260 2.08 8.75 10.83 28 50 250 300 1.79 8.93 10.72 15 29 50 265 315 1.72 9.14 10.86 32 50 350 400 1.56 10.94 12.503编辑ppt 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 7 18 ? 157 207 2.78 8.72 11.50 21 ? 182 232 2.38 8.67 11.05 23 ? 200 250 2.17 8.70 10.87 10 24 ? 210 260 2.08 8.75 10.83 28 ? 250 300 1.79 8.93 10.72 15 29 ? 265 315 1.72 9.14 10.86 32 ? 350 400 1.56 10.94 12.50 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVCThefirstcolumnisthequantityofcarsyourfactorycanproduceinthousandsandthesecondcolumnsimplyrepresentsyourfirm’sfixedcosts.Thesefixedcostsaresometimescalled“overhead”or“sunkcosts”andfixedcostsarethosecoststhatdonotchangewiththelevelofoutput.

4编辑ppt 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVC 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 7 18 ? 157 207 2.78 8.72 11.50 21 ? 182 232 2.38 8.67 11.05 23 ? 200 250 2.17 8.70 10.87 10 24 ? 210 260 2.08 8.75 10.83 28 ? 250 300 1.79 8.93 10.72 15 29 ? 265 315 1.72 9.14 10.86 32 ? 350 400 1.56 10.94 12.50Examplesofsuchfixedcostsincluderent,interestonthebondsyouissuedtogetmoneytobuildyourfactory,insurancepremiums,thesalariesoftopmanagement,andsoon.505050505050505编辑ppt 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVC 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 7 18 50 157 207 2.78 8.72 11.50 21 50 182 232 2.38 8.67 11.05 23 50 200 ? 2.17 8.70 10.87 10 24 50 210 ? 2.08 8.75 10.83 28 50 250 ? 1.79 8.93 10.72 15 29 50 265 ? 1.72 9.14 10.86 32 50 350 ? 1.56 10.94 12.50Variablecostsaresimplythosecoststhatchangewiththelevelofoutput.Bydefinition,VCbeginsatzerowhenqiszero.250260300315400+=Rawmaterials,fuel,andwagesareallvariablecosts.Notethattotalcostissimplyvariablecostsplusfixedcosts.6编辑pptTotalcostinshortrun:inlongrun:TotalcostVariablecost=FixedcostVariablecost+7编辑ppt 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVC 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 ? 18 50 157 207 2.78 8.72 11.50 21 50 182 232 2.38 8.67 11.05 23 50 200 250 2.17 8.70 10.87 ? 24 50 210 260 2.08 8.75 10.83 28 50 250 300 1.79 8.93 10.72 ? 29 50 265 315 1.72 9.14 10.86 32 50 350 400 1.56 10.94 12.50Marginalutilityistheadditionalutilityaconsumergetsfromaone-unitincreaseinconsumption.Howwouldyoudefinemarginalcost?8编辑pptMarginalcostTheconceptofmarginalcostisoneofthemostessentialinmicroeconomics.Marginalcost(MC)denotestheextraoradditionalcostofproducing1extraunitofoutput.9编辑pptForanairlineflyingplaneswithemptyseats,theaddedcostofanotherpassengerisquitelow.Butonahotsummerday,wheneveryone’sconditionersarerunning,theaddedelectricpowercomesatahighmarginalcost.10编辑ppt 1 2 3 4 5 6 7 8 Marginalcosts Average Averagevariable Averagetotal Fixed Variable Total (MC) fixedcosts fixedcostscosts(ATC) costs costs costs (changein (AFC) (AVC) (ATC)Output (FC) (VC) (TC) totalcosts) FC/Output VC/Output AFC+AVC 4 50 50 100 12.50 12.50 25.00 10 5 50 60 110 10.00 12.00 22.00

10 50 100 150 5.00 10.00 15.00 6 11 50 106 156 4.54 9.64 14.18 17 50 150 200 2.94 8.82 11.76 7 18 50 157 207 2.78 8.72 11.50 21 50 182 232 2.38 8.67 11.05 23 50 200 250 2.17 8.70 10.87 10 24 50 210 260 2.08 8.75 10.83 28 50 250 300 1.79 8.93 10.72 15 29 50 265 315 1.72 9.14 10.86 32 50 350 400 1.56 10.94 12.50fallriseMC=TCq－TCq-1=(VCq＋FC)－(VCq-1＋FC)=VCq－VCq-111编辑pptTotalCostandMarginalCostOutputTotalcostOutputMarginalcost12编辑pptTheSupplyCurveAggregateandmarginalcost(dollars)QuantityAVCACMCThesupplycurveisthatportionofthemarginalcostcurveabovetheaveragevariablecostcurve.13编辑ppt中国案例分析2：中山大学校区调整2000年中山大学珠海校区正式招生，开启了中国高等学府异地办学的“中大模式”。2004年大学城建设正式完工，中大面临着两难选择：要不选择离广州较近的东校区（已有土地）进行新的大楼建设和新生扩招，或者是继续在已投资10亿元的珠海校区完善教学设施和科研环境。但是……（此处省略一万字）2006年IBS诞生了。请评论。14编辑ppt课堂测试在MP曲线向下倾斜的产量内：A、MC曲线向下倾斜B、AFC曲线向上倾斜C、企业处于规模经济中D、总成本曲线向上倾斜15编辑pptAveragecostAveragecost(orunitcost)=totalcostoutput=TCq=ACAveragefixedcost=fixedcostoutput=FCq=AFCAveragevariablecost=variablecostoutput=VCq=AVC16编辑pptAggregateandmarginalcost(dollars)QuantityAVCMCAFCATCqTheAFCcurveapproacheszerobecauseasafirm’soutputincreases,itspreadsitsfixedcostsoveralargernumberofunitssoaveragefixedcostsmustfall.Forthesamereason,theAVCcurvemustapproachtheATCcurveasoutputincreases.AFC,AVCAndACCurves17编辑pptTheRelationofACandMCACq+1=ACq×q＋MCq+1q＋1=ACq×(q＋1)＋MCq+1－ACqq＋1=

ACq＋MCq+1－ACqq＋118编辑pptConclusionIfMC>AVC,thenAVCisrising.IfMC=AVC,thenAVCisatitslowpoint.IfMC<AVC,thenAVCisfalling.QuantityACandMC=

AVCq＋MCq+1－AVCqq＋1AVCq+1AVC19编辑pptRelationbetweenSlopeandMarginalCostTangentlineTotalcostcurve1unitofoutputMarginalcosta20编辑pptTheLinkbetweenProductionandCostsThecostcurveforafirmdependsverycloselyon①thepricesofinputsand②thefirm’sproductionfunction.Ifyouknowfactorpricesandtheproductionfunction,youcancalculatethecostcurve.21编辑pptDiminishingReturnsandProduceUpward-SlopeMCLaborMarginalproductoflaborMarginalcostOutputABDABDMCACIntheshortrun:22编辑ppt课堂测试假设在短期内劳动是唯一的可变投入，并且劳动价格是常数，你能根据平均产量曲线和边际产量曲线的形状解释AVC曲线和MC曲线为什么成U型？23编辑pptLeast-CostRuleToagivenoutput:MarginalproductofinputAPriceofinputA=MarginalproductofinputBPriceofinputB=……24编辑pptThisgivesyouthemarginalproductperdollarofoutput.EquimarginalPrinciple25编辑ppt课堂测试已知生产函数为Y=25/8L3/8K5/8，生产要素L和K的价格分别为3和10。试求：（1）厂商的生产函数最优组合

（2）如果资本的数量K=9时，厂商的短期成本函数

（3）厂商的长期成本函数26编辑pptSubstitutionRuleIfthepriceofonefactorfallswhileallotherfactorpricesremainthesame,firmswillprofitbysubstitutingthenow-cheaperfactorforalltheotherfactors.MPofLaborPriceofLabor=MPofCapitalPriceofCapital27编辑pptTheLongRunAverageCostCurveQuantityCostsperunitSATC7SATC6SATC5SATC4SATC3SATC2SATC1LATCThelongrunaveragecostcurveistheenvelopeoftheshortrunaveragecostcurves.CapitalinputsarefixedintheshortrunandthereisapointontheATCcurvewhereaveragecostisminimized.28编辑pptTheLongRunAverageCostCurveQuantityCostsperunitSATC7SATC6SATC5SATC4SATC3SATC2SATC1LATCIfthenumberofpossibleplantsizesisverylarge,thelongrunaveragecostcurveapproximatesasmoothcurve.29编辑ppt课堂测试“一个厂商如果现在的产量水平处于这个产量水平的平均成本最低点，而这时长期平均成本处于上升阶段，于是可得出结论：这时短期边际成本大约短期平均成本”。你认为这句话对吗？30编辑pptEconomicvs.AccountingProfitsLet’stalkabouthowaneconomistmeasuresafirm’scostsandprofitsversushowanaccountantmeasuresthem.Inthisregard,aneconomist–asopposedtoanaccountant–willalwayscountnotonlyexplicitcostsbutimplicitcostsaswell.31编辑pptOpportunityCostsIncludesallconsequences,whethertheyreflectexplicitmonetarytransactionsornot.Theimmediatedollarcostofgoingtoamovieinsteadofreadingyoureconomicstextbookisthepriceofthemovieticket.Theopportunitycostalsoincludesthepossibilityofgainingabetterunderstandingofmacroeconomicsandthereforebecomingmoresuccessfulinbusiness.32编辑pptSupposebothyouandyourspouseearnaftertaxsalariesof$45,000ayearassalesrepresentativesforahospitalequipmentdistributor,butyouwanttodobetter.Youborrow$20,000fromthebankat10%interest.Youkickinanother$30,000ofyourownsavingsthathadbeenearningyou$1,500annuallyininterestincomefromyourportfolioofbondinvestments.Youalsokickoutatenantinthestorefrontthatyouownwhowaspayingyou$800inrentpermonth.ACaseofOpportunityCosts33编辑pptYourownfinancialcapital $1,500Kickingoutyourtenant 7,200Aftertaxsalaries 90,000Total $98,700Accountingprofit $90,450Economicprofit -$8,250Category OpportunityCostYouEndUpBeingWorseOff34编辑ppt生产、成本理论和企业决策附录编辑ppt生产函数的数值例子Q=1002LAQ=output;L=labor;A=land.Theproductionfunctionisaconstant-returns-to-scaleproductionfunction,aspecialcaseoftheCobb-Douglasproductionfunction.36编辑ppt3464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456ConstantreturnstoscaleLaborLand37编辑ppt3464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456DiminishingmarginalproductoflaborLaborLand826454484238编辑ppt346490600692775846316448548632705775282400490564632692