第五章微觀經(jīng)濟(jì)學(xué)成本論

第五章本錢實(shí)際CH5TheCostTheoryCONTENTS第一節(jié)本錢的概念第二節(jié)短期本錢實(shí)際第三節(jié)長期本錢實(shí)際第一節(jié)本錢的概念5-1TheConceptofCost一、時(shí)機(jī)本錢

〔opportunitycost〕是指假設(shè)一定消費(fèi)要素被用來消費(fèi)某種產(chǎn)品，便放棄了用在其他用途上的能夠獲得的收益，這筆收益就是消費(fèi)這種產(chǎn)品的時(shí)機(jī)本錢。二、顯本錢與隱本錢1、顯本錢〔explicitcost〕指廠商購買消費(fèi)要素支付貨幣所構(gòu)成的本錢，是一種會(huì)計(jì)本錢。2、隱本錢〔implicitcost〕隱本錢指廠商運(yùn)用自有消費(fèi)要素而支付的費(fèi)用。兩者區(qū)別:購買的消費(fèi)要素的一切權(quán)歸誰？三、利潤〔profit〕總本錢=顯本錢+隱本錢經(jīng)濟(jì)利潤=總收益—總本錢，簡稱“利潤〞經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別正常利潤：廠商對(duì)本人所提供的企業(yè)家才干所支付的報(bào)酬，是隱本錢的一種。會(huì)計(jì)利潤=總收益—顯本錢經(jīng)濟(jì)利潤=總收益—顯本錢—隱本錢。〔不包括正常利潤〕總收益經(jīng)濟(jì)學(xué)家眼中的利潤會(huì)計(jì)師眼中的利潤經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別與聯(lián)絡(luò)顯性本錢會(huì)計(jì)本錢(只需顯性本錢)TotalRevenue經(jīng)濟(jì)學(xué)家眼中的利潤會(huì)計(jì)師眼中的利潤經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別與聯(lián)絡(luò)顯性本錢會(huì)計(jì)本錢(只需顯性本錢)會(huì)計(jì)利潤TotalRevenue經(jīng)濟(jì)學(xué)家眼中的利潤會(huì)計(jì)師眼中的利潤經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別與聯(lián)絡(luò)隱性本錢〔包括正常利潤〕顯性本錢會(huì)計(jì)本錢(只需顯性本錢)會(huì)計(jì)利潤TotalRevenue經(jīng)濟(jì)學(xué)家眼中的利潤會(huì)計(jì)師眼中的利潤經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別與聯(lián)絡(luò)經(jīng)濟(jì)利潤隱性本錢〔包括正常利潤〕顯性本錢會(huì)計(jì)本錢(只需顯性本錢)會(huì)計(jì)利潤TotalRevenue經(jīng)濟(jì)學(xué)家眼中的利潤會(huì)計(jì)師眼中的利潤經(jīng)濟(jì)利潤與會(huì)計(jì)利潤的區(qū)別與聯(lián)絡(luò)2024/2/512例：會(huì)計(jì)師的算法經(jīng)濟(jì)學(xué)家的算法項(xiàng)目數(shù)量項(xiàng)目數(shù)量銷售收益原材料費(fèi)用水電費(fèi)工資銀行利息300000130000100005000010000銷售收益原材料費(fèi)用水電費(fèi)工資銀行利息300000130000100005000010000隱含租金隱含利息隱含工資500001000040000會(huì)計(jì)成本200000經(jīng)濟(jì)成本300000會(huì)計(jì)利潤100000經(jīng)濟(jì)利潤0第二節(jié)短期本錢實(shí)際5-2TheShort-runCostTheory一、短期總產(chǎn)量曲線與

短期總本錢曲線FromTPLtoSTC,……2024/2/5151、消費(fèi)函數(shù)、本錢函數(shù)與本錢方程消費(fèi)函數(shù)：描畫的是一定技術(shù)條件下要素與最大產(chǎn)量間的技術(shù)關(guān)系。本錢函數(shù)：建立在技術(shù)關(guān)系之上的本錢與產(chǎn)量間的經(jīng)濟(jì)關(guān)系。本錢方程：表示消費(fèi)本錢與消費(fèi)要素的投入量之間的關(guān)系。2、短期總本錢函數(shù)STC〔Q〕2024/2/517由短期總產(chǎn)量曲線推導(dǎo)短期總本錢曲線(b)短期總本錢曲線Cost500200STC(Q)

w·L(Q)Fixedcostr·K25050125150125(a)總產(chǎn)量曲線L100

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2530691215150QQ2024/2/518二、短期總本錢和擴(kuò)展線的關(guān)系oLＱ1Ｑ2Ｑ3A2E3K3A3A1B1B2B3K2K1L1L2L3E2E1K擴(kuò)展線短期總本錢大于或者等于長期總本錢擴(kuò)展線是斜率等于本錢線的等斜線。三、短期本錢曲線〔一〕、七種短期本錢1.短期總本錢(TC、TFC、TVC)Tobecontinued2、短期平均本錢1〕AC〔Q〕=TC/Q2〕AFC〔Q〕=TFC/Q3〕AVC〔Q〕=TVC/QTobecontinued3.邊沿本錢：MC=MarginalCostTFC=TotalFixedCostsTVC=TotalVariableCostsAVC=AverageVariableCostsTC=TotalCostsA〔T〕C=AverageTotalCosts七種短期本錢的縮寫方式AFC=AverageFixedCosts〔二〕、七種短期本錢的幾何圖形CQCQTFCCQTFCTVCTCa.總不變本錢曲線b.總可變本錢曲線c.總本錢曲線TobecontinuedCQCQCQCQAFCAVCACMCd.平均不變本錢曲線f.平均總本錢曲線e.平均可變本錢曲線g.邊沿本錢曲線〔三〕七種短期本錢曲線的綜合圖平均本錢等于總本錢曲線上各點(diǎn)與原點(diǎn)連線的斜率；邊沿本錢等于總本錢曲線上各點(diǎn)切線的斜率。留意“拐點(diǎn)〞。2024/2/526短期本錢曲線綜合圖示COQOCQTFCAFCTVCAVCTCACMCTC與TVC都隨Q的添加而添加，兩線平行，其間隔就是TFCAC與AVC的間隔隨Q的增大而越來越近，其緣由在于AFC的遞減。AMC相交于AVC的最低點(diǎn)。此時(shí)從原點(diǎn)出發(fā)到AVC曲線A點(diǎn)的射線與其切線重合。MC相交于AC的最低點(diǎn)。此時(shí)從原點(diǎn)出發(fā)到AC曲線B點(diǎn)的射線與其切線重合。BD與MC曲線的最低點(diǎn)D’相對(duì)應(yīng)，TC和TVC都出現(xiàn)拐點(diǎn)，從此它們上升的斜率變大。TFC與Q無關(guān)，AFC隨著Q的添加而遞減。CD’綜合圖的分解之一：TC、TFC與TVC參與TFC到TVC意味著在總可變本錢曲線上參與一樣的固定本錢量。所以，總本錢曲線與總可變本錢曲線外形一樣，只是高出一個(gè)等于總不變本錢TFC的量。綜合圖的分解之二：AC、AFC與AVC由于AFC隨Q的添加而下降，不斷遞減的本錢量參與AVC得到ATC，兩者間隔隨Q的增大而越來越近。2024/2/529綜合圖的分解之三：AC、AVC與MC假設(shè)MC低于AC、AVC，AC、AVC下降；反之那么反之。MC曲線與AC、AVC曲線相交于各自的最低點(diǎn)?！菜摹?、由TC曲線到AC曲線和MC曲線平均本錢等于總本錢曲線上各點(diǎn)與原點(diǎn)連線的斜率；邊沿本錢等于總本錢曲線上各點(diǎn)的切線的斜率。2024/2/5311、由TFC曲線推導(dǎo)AFC曲線TFCAFCAFC是TFC上的各點(diǎn)與原點(diǎn)連線的斜率值的軌跡。2024/2/5322、由TVC曲線推導(dǎo)AVC曲線AVC是TVC線上各點(diǎn)與原點(diǎn)連線的斜率值的軌跡。A點(diǎn)是AVC的最低點(diǎn)。ACQTVCAVC3、由TC曲線推導(dǎo)AC曲線AC是TC曲線上的點(diǎn)與原點(diǎn)連線斜率值的軌跡。B點(diǎn)是AC的最低點(diǎn)。ABCQTCACO2024/2/5344、AVC和AC最低點(diǎn)的比較由于TVC的射線與切線重合點(diǎn)在TC之前出現(xiàn)，所以AVC的最低點(diǎn)在AC之前。AVCACTCTVC5、由TC或者TVC曲線推導(dǎo)MC曲線MC是TVC〔TC〕曲線對(duì)應(yīng)點(diǎn)導(dǎo)數(shù)的軌跡；B點(diǎn)是一重要拐點(diǎn)，它是TVC曲線斜率最小之處，對(duì)應(yīng)B’點(diǎn)。CQTVCMCBB’0拐點(diǎn)B處一階導(dǎo)數(shù)最小，且二階導(dǎo)數(shù)為零。比較:MC曲線與AC、AVC曲線MC曲線先到達(dá)最低點(diǎn)；MC分別與AVC或AC曲線在各自最低處相交。QCMCACAVCMarginalCost=MCTotalFixedCosts=TFCTotalVariableCosts=TVCAverageVariableCosts=AVCTotalCosts=TCAverageTotalCosts=ATCAverageFixedCosts=AFCSummaryofDefinitions...QuantityCosts(dollars)CostsGraphicallyPresented...QuantityCosts(dollars)TVCVariableCostCostsGraphicallyPresented...QuantityCosts(dollars)TFCCostsGraphicallyPresented...QuantityCosts(dollars)TFCCombiningwithvariablecost...CostsGraphicallyPresented...QuantityCosts(dollars)CostsGraphicallyPresented...TVCVariableCostQuantityCosts(dollars)AddverticallytogetTotalCostCostsGraphicallyPresented...TFCTVCVariableCostQuantityCosts(dollars)TCTotalCostFixedCostCostsGraphicallyPresented...TVCVariableCostTFCQuantityShort-runaveragecosts(dollars)PlottingAverageCostsCostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCCostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCAVCCostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCAVCAddverticallytoget...CostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCAVCATCCostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCAVCATCPlottingthechangesintotalcostyields...CostsGraphicallyPresented...QuantityShort-runaveragecosts(dollars)AFCAVCATCMCCostsGraphicallyPresented...2024/2/552〔五〕、短期本錢變動(dòng)的決議要素：

邊沿報(bào)酬遞減規(guī)律回想：邊沿報(bào)酬遞減規(guī)律MPL先升后降2024/2/553TotalProduct,TPQuantityofLaborAverageProduct,AP,andmarginalproduct,MPQuantityofLabor再閱讀一遍：LawofDiminishingReturnsMarginalProductAverageProductTotalOutputIncreasingMarginalReturns2024/2/554TotalProduct,TPQuantityofLaborAverageProduct,AP,andmarginalproduct,MPQuantityofLaborLawofDiminishingReturnsDiminishingMarginalReturnsMarginalProductAverageProductTotalOutput2024/2/555TotalProduct,TPQuantityofLaborAverageProduct,AP,andmarginalproduct,MPQuantityofLaborTotalOutputMarginalProductAverageProductNegativeMarginalReturnsLawofDiminishingReturns2024/2/556MPL與MC的關(guān)系在短期消費(fèi)中，MPL遞增階段對(duì)應(yīng)MC遞減階段；MPL遞減階段對(duì)應(yīng)MC遞增階段；MPL最大值對(duì)應(yīng)MC最小值。2024/2/557MPL與MC的關(guān)系圖示QuantityoflaborCosts(dollars)AverageproductandmarginalproductQuantityofoutputProductivity&CostCurveRelationshipQuantityoflaborCosts(dollars)AverageproductandmarginalproductQuantityofoutputMPMCProductivity&CostCurveRelationshipQuantityoflaborCosts(dollars)AverageproductandmarginalproductQuantityofoutputMPAPMCAVCProductivity&CostCurveRelationship〔六〕短期產(chǎn)量曲線與短期本錢曲線之間的關(guān)系短期消費(fèi)函數(shù)短期本錢函數(shù)為1、邊沿產(chǎn)量和邊沿本錢246MPL0 4 10369MCCQL根據(jù)邊沿本錢定義，得：2024/2/563QuantityofoutputMPMC邊沿產(chǎn)量曲線與邊沿本錢曲線之間的關(guān)系QC00LQ邊沿報(bào)酬遞減規(guī)律決議了曲線的外形！APAVC2、、平均產(chǎn)量和平均可變本錢Labor246MPAPLabor0 4 10369MCAVCCACQTFC短期消費(fèi)函數(shù)和短期本錢函數(shù)之間的對(duì)應(yīng)關(guān)系QL0TPL·

QLMPLAPLQCACAVCCQTCTVC0(a)(b)(c)(d)MC邊沿本錢處于上升階段，平均可變本錢也越過最低點(diǎn)，處于遞增形狀TFC短期消費(fèi)函數(shù)和短期本錢函數(shù)之間的對(duì)應(yīng)關(guān)系QL0TPL·

QLMPLAPLQCACAVCCQTCTVC0(a)(b)(c)(d)MC第二階段：經(jīng)濟(jì)區(qū)域2024/2/567MarginalCost=MCTotalFixedCosts=TFCTotalVariableCosts=TVCAverageVariableCosts=AVCTotalCosts=TCAverageTotalCosts=ATCAverageFixedCosts=AFCSummaryofDefinitions...2024/2/568QuantityCosts(dollars)CostsGraphicallyPresented...2024/2/569QuantityCosts(dollars)TVCVariableCostCostsGraphicallyPresented...2024/2/570QuantityCosts(dollars)TFCCostsGraphicallyPresented...2024/2/571QuantityCosts(dollars)TFCCombiningwithvariablecost...CostsGraphicallyPresented...2024/2/572QuantityCosts(dollars)CostsGraphicallyPresented...TVCVariableCost2024/2/573QuantityCosts(dollars)AddverticallytogetTotalCostCostsGraphicallyPresented...TFCTVCVariableCost2024/2/574QuantityCosts(dollars)TCTotalCostFixedCostCostsGraphicallyPresented...TVCVariableCostTFC2024/2/575QuantityShort-runaveragecosts(dollars)PlottingAverageCostsCostsGraphicallyPresented...2024/2/576QuantityShort-runaveragecosts(dollars)AFCCostsGraphicallyPresented...2024/2/577QuantityShort-runaveragecosts(dollars)AFCAVCCostsGraphicallyPresented...2024/2/578QuantityShort-runaveragecosts(dollars)AFCAVCAddverticallytoget...CostsGraphicallyPresented...2024/2/579QuantityShort-runaveragecosts(dollars)AFCAVCATCCostsGraphicallyPresented...2024/2/580QuantityShort-runaveragecosts(dollars)AFCAVCATCPlottingthechangesintotalcostyields...CostsGraphicallyPresented...2024/2/581QuantityShort-runaveragecosts(dollars)AFCAVCATCMCCostsGraphicallyPresented...第三節(jié)長期本錢實(shí)際5-3TheLong-runCostTheory2024/2/583Long-runorShort-runCost？2024/2/584LTC曲線、LAC曲線和LMC曲線總本錢平均本錢邊沿本錢產(chǎn)量產(chǎn)量〔a〕〔b〕0LACLMCLTC一、LTC函數(shù)和LTC曲線由長期消費(fèi)函數(shù)和本錢方程，得最優(yōu)消費(fèi)規(guī)模選擇和LTC曲線每條STC曲線代表一種消費(fèi)規(guī)模。a、b、c是STC曲線與LTC曲線的切點(diǎn)，表示不同產(chǎn)量下的最低總本錢。STC1STC2STC3LTC0QCdebacQ1Q2Q32024/2/587LTC曲線LTC線是STC線的包絡(luò)線。包絡(luò)線〔envelope-curve〕是指LTC線把無數(shù)條STC線包圍起來的連線。在包絡(luò)線上，每一條STC線與LTC線不相交但相切。擴(kuò)展線和LTC曲線oA2A3A1KB1B2B3Low·OB3=r·OA3C50100150QE3E2E1擴(kuò)展線Ｑ1=50Ｑ3=150Ｑ2=100RLTCw·OB2=r·OA2w·OB1=r·OA12024/2/589REVIEW：擴(kuò)展線和STCoLＱ1Ｑ2Ｑ3A2E3K3A3A1B1B2B3K2K1L1L2L3E2E1K擴(kuò)展線STC≥LTC擴(kuò)展線是斜率等于本錢線的等斜線。二、長期平均本錢2024/2/591LAC曲線的推導(dǎo)〔一〕LTC曲線上各點(diǎn)與原點(diǎn)的連線的斜率值，即為LAC曲線。00CCQQLTCLACBAA’B’CC’LAC曲線的推導(dǎo)〔二〕LAC曲線是無數(shù)條SAC曲線的包絡(luò)線。0QCSAC1SAC2SAC3C1Q1Q2Q1’C2Q2’C3Q3CostsOutputForeveryplantcapacitysize...thereisashort-runACcurveandeveryAChasaminimumcost每條SAC曲線代表一種規(guī)模的消費(fèi)平均本錢COutputAninfinitenumberofsuchcostcurvescanbeconstructed...無數(shù)不同規(guī)模的SAC曲線LAC與SAC最低點(diǎn)的右邊相切LAC與SAC最低點(diǎn)的左邊相切TheLong-runACjust“envelopes〞alloftheshort-runACcurvesCOutput構(gòu)成LAC曲線LAC曲線是SAC曲線的包絡(luò)線：SAC曲線與LAC曲線切點(diǎn)的連線。留意：LAC曲線不一定是SAC曲線的最低點(diǎn)連線。LACOutput分析LAC曲線的外形CLAC曲線是條“U〞型曲線，表示在企業(yè)消費(fèi)擴(kuò)張的開場階段，由于擴(kuò)展消費(fèi)規(guī)模而使經(jīng)濟(jì)效益得到提高，此為規(guī)模經(jīng)濟(jì)〔內(nèi)在經(jīng)濟(jì)〕；然后，隨著企業(yè)規(guī)模的擴(kuò)展，經(jīng)濟(jì)效益下降，此為規(guī)模不經(jīng)濟(jì)〔內(nèi)在不經(jīng)濟(jì)〕。規(guī)模經(jīng)濟(jì)規(guī)模不經(jīng)濟(jì)2024/2/597規(guī)模經(jīng)濟(jì)〔economiesofScale〕的緣由不可分性投入本錢的分?jǐn)偼度氲膶I(yè)化2024/2/598不可分性投入本錢的分?jǐn)傄粋€(gè)計(jì)算機(jī)芯片公司中的無菌車間、精細(xì)儀器和檢驗(yàn)設(shè)備；船商橫渡大西洋，將電視機(jī)從日本運(yùn)往美國所運(yùn)用的大型輪船；比薩餅店運(yùn)用的烤爐；有線電視公司在其領(lǐng)域內(nèi)鋪設(shè)的電纜；嚇跑海獅的假食人鯨模具。2024/2/599投入的專業(yè)化分工提高效率〔亞當(dāng)．斯密〕AdamSmith，TheWealthofNations〔NewYork：TheModernLibrary，1937〕，pp.4-5.2024/2/5100規(guī)模不經(jīng)濟(jì)〔DiseconomiesofScale〕的緣由協(xié)調(diào)問題遞增的投入本錢2024/2/5101Q0CLAC2LAC1LAC位置平行下降，是外在經(jīng)濟(jì)的表現(xiàn)。LAC曲線的挪