成本的经济分析

1、成本分析第7章1成本的经济分析7.12短期短期The short run: The period in which firms can adjust production only by changing variable factors such as materials and labor but cannot change fixed factors such as capital.3固定成本固定成本The cost related to fixed factors is called fixed cost (固定成本，不变成本固定成本，不变成本).A firms fixed costs

2、, sometimes called “overhead” (企业一般管理费用企业一般管理费用) or “sunk costs” (沉入成本沉入成本), must be paid even if the firm produces no output, and they will not change if output changes.4变动成本变动成本The cost related to variable factors is called variable cost (变动成本，可变成变动成本，可变成本本).Variable costs are those which vary as

3、output changes. By definition, VC begins at zero when q is zero.5总成本是可达到的最小成本总成本是可达到的最小成本Total cost represents the lowest total dollar expense needed to produce each level of output q. 说明：说明：与生产函数的处理类似，总成本与生产函数的处理类似，总成本也是指给定产量时的最小成本，目的是也是指给定产量时的最小成本，目的是为了让函数关系具有唯一性。为了让函数关系具有唯一性。6Totalcostin short ru

4、n:in long run:TotalcostVariablecost=FixedcostVariablecost+7(1)(2)(3)(4)QuantityFixed costVariable costTotal cost=(2)+(3)qFC($)VC($)TC($)055055155308525555110355751304551051605551552106552252808边际成本边际成本The concept of marginal cost is one of the most essential in microeconomics. Marginal cost (MC) den

5、otes the extra or additional cost of producing 1 extra unit of output.9For an airline flying planes with empty seats, the added cost of another passenger is quite low.But on a hot summer day, when everyones conditioners are running, the added electric power comes at a high marginal cost.10边际成本的计算边际成

6、本的计算(1)(2)(3)OutputTotal costMarginal costQTC($)MC($)0551852110313041605210302520305011利用变动成本计算边际成本利用变动成本计算边际成本(1)(2)(3)OutputVariable costMarginal costQVC($)MC($)0013025537541055155302520305012MC = TCq+1 TCq = (VCq+1FC) (VCqFC)= VCq+1 VCq数学推导数学推导为什么可以用变动成本来计算边际成本：为什么可以用变动成本来计算边际成本：13总成本和边际成本的关系总成本和

7、边际成本的关系OutputTotal costOutputMarginal cost14平均成本平均成本Average cost(or unit cost)=total costoutput=TCq=ACAveragefixed cost=fixed costoutput=FCq= AFCAveragevariable cost=variable costoutput=VCq= AVC15总成本、固定成本和变动成本总成本、固定成本和变动成本Total costVariable costFixed costQuantityCost16平均成本和边际成本平均成本和边际成本QuantityAvera

8、ge and marginal costMCACAVCAFC平均成本最小平均成本最小平均变动成本最小平均变动成本最小17平均成本与边际成本的关系平均成本与边际成本的关系成本成本产量产量边际成本边际成本平均成本平均成本平均成本最低点平均成本最低点边际成本曲边际成本曲线自下而上线自下而上穿越平均成穿越平均成本曲线的最本曲线的最低点。低点。18平均成本平均成本 边际成本边际成本成本成本产量产量边际成本边际成本平均成本平均成本边际成本边际成本平均成本平均成本,平平均成本随着均成本随着产量增加而产量增加而向下向下。16元元2212元元19平均成本平均成本 边际成本边际成本成本成本产量产量边际成本边际成本

9、平均成本平均成本17元元边际成本边际成本 平均成本平均成本,平平均成本随着均成本随着产量增加而产量增加而向上向上。23元元5020边际成本和平均成本的关系边际成本和平均成本的关系ACq+1=ACqqMCq1=ACq(q1) MCACqq1= ACqMCACqq121小结小结QuantityAC and MC= ACqMCACqq1ACq+1AC22边际成本和平均变动成本的关系边际成本和平均变动成本的关系AVCq+1=AVCqqMCq1=AVCq(q1) MCAVCqq1= AVCqMCAVCqq123小结小结QuantityAC and MC= AVCqMCAVCqq1AVCq+1AVC24斜

10、率和边际成本的关系斜率和边际成本的关系Tangent lineTotal cost curve1 unit of outputMarginal costaaTCMCQ25产量与成本之间的联系产量与成本之间的联系The cost curve for a firm depends very closely on the prices of inputs and the firms production function.If you know factor prices and the production function, you can calculate the cost curve.26

11、(1)(2)(3)(4)(5)(6)OutputLandLaborRentWageTotal cost(tons)(acres)(workers)($/acre)($/worker)($)01005.555511065.55?210115.55110310155.55130410215.55160510315.55?610455.55280710635.55370810855.554808521027报酬递减和报酬递减和UU形成本曲线形成本曲线LaborMarginal product of laborMarginal costOutputABDABDMCACIn the short run:

12、28最小成本规则最小成本规则To a given output:Marginal product of input A APrice of input A A=Marginal product of input B BPrice of input B B=29等边际原理等边际原理BBAAMPPMPP1$1$This gives you the marginal product per dollar of output.30替代规则替代规则If the price of one factor falls while all other factor prices remain the same,

13、 firms will profit by substituting the now-cheaper factor for all the other factors.MP of LaborPrice of Labor=MP of CapitalPrice of Capital31背景知识背景知识在资本主义由工场手工业向大机器生产过渡的历史时期，由于机器操作的简单性，女工、童工加入劳动行列，劳动供给增加。与此同时，大机器生产要求相对较多的资本，资本的供给相对稀缺。这是导致工人当时生活贫困的主要原因。当资本不断积累，而生产又要求较为复杂的劳动技能时，在要素市场上，资本不可能总是处于有利的竞争地位

14、。32短期成本与长期成本的关系成本成本产量产量长期平均成本长期平均成本1 亩地亩地2 亩地亩地4 亩地亩地3 亩地亩地1 亩地亩地更有利更有利2 亩地亩地更有利更有利3 亩地亩地更有利更有利4 亩地亩地更有利更有利33规模经济与规模不经济成本成本产量产量长期平均成本长期平均成本规模经济规模经济规模不经济规模不经济34经济成本和企业会计7.235经济成本和会计成本经济成本和会计成本经济成本经济成本（economic cost）：投入生产）：投入生产的所有资源的机会成本。的所有资源的机会成本。会计成本会计成本（accounting cost）：按照会计）：按照会计规则计算的成本规则计算的成本在会计

15、帐面上显示出来的经济成本称为在会计帐面上显示出来的经济成本称为外显（显性）成本外显（显性）成本（explicit costs），在），在会计帐面上不能显示出来的经济成本称会计帐面上不能显示出来的经济成本称为为内含（隐性）成本内含（隐性）成本（implicit costs）。）。36经济利润经济成本经济成本 = 外显成本外显成本 + 内含成本内含成本 = 机会成本机会成本经济利润经济利润 = 销售收入销售收入 经济成本经济成本经济利润是计入了所有使用的资源代价经济利润是计入了所有使用的资源代价后的纯收益。后的纯收益。37一个体饭馆业主使用自己的一个体饭馆业主使用自己的店面，店面， 1年盈利年盈利

16、3万元，这个万元，这个3万元称之为会计利润。万元称之为会计利润。若不开饭馆，在所有可选工作中若不开饭馆，在所有可选工作中最高可赚得最高可赚得2万元，人力的经济成万元，人力的经济成本就是本就是2万元。如果店面用于出租万元。如果店面用于出租可以获得可以获得1.5万元租金，那么店面万元租金，那么店面的经济成本就是的经济成本就是1.5 万元。万元。考虑到经济成本后，这个个体饭馆业主的经考虑到经济成本后，这个个体饭馆业主的经济利润为济利润为0.5 万元。万元。38收益表收益表(1)Net sales$250,000Less cost of goods sold:(2) Materials$50,000(

17、3) Labor cost90,000(4) Miscellaneous operating costs10,000(5)Less overhead costs:(6) Selling and administrative costs15,000(7) Rent for building5,000(8) Depreciation15,000(9)Operating expenses$185,000185,000(10) Net operating income$65,00039收益表收益表(10) Net operating income$65,000Less:(11) interest ch

18、arges on equipment loan6,000(12) State and local taxes4,000(13) Net income before income taxes$55,000(14) Less: Corporation income taxes18,000(15) Net income (or profit) after taxes$37,000(16) Less: Dividends paid on common stock15,000(17) Addition or retained earnings$22,00040The depreciation is ta

19、ken in annual accounting charges over the assets accounting lifetime折旧折旧$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000$10,000depreciation = the capital goods historical cost or purchase price.Depreciation = the annual cost of a capital input that a company actually owns itself.41资产负

20、债表资产负债表AssetsLiabilities and net worthLiabilitiesCurrent assets:Current liabilities: Cash$20,000 Accounts payable$20,000 Inventory80,000 Notes payable30,000Fixed assets:Long-term liabilities: Equipment150,000 Bonds payable100,000 Buildings100,000 Net worthStockholders equity:_ Common stock200,000Tot

21、al$350,000 Total$350,00042关于资产负债表关于资产负债表The income statement measures the flows into and out of the firm, while the balance sheet measures the stocks of assets and liabilities at the end of the accounting year.A balance sheet must always balance:Total assets = total liabilities + net worth43例子例子Supp

22、ose total assets are down $40,000; liabilities remain unchanged. This means total net worth has decreased by $40,000, and should write net worth down from the previous $200,000 to only $160,000.AssetsLiabilities and net worthLiabilities$40,000Net worthCommon stock $40,00044会计惯例会计惯例The value placed o

23、n almost every item reflects its historical costs.45说明说明“收入表收入表”是描述一指定会计时间段中是描述一指定会计时间段中货币流入和流出企业的情况。货币流入和流出企业的情况。“资产负债表资产负债表”是指在某一特定的会计是指在某一特定的会计时刻，企业的资产、负债和所有者权益时刻，企业的资产、负债和所有者权益状况。状况。总之，总之，“收入表收入表”是对一时段而言的，是对一时段而言的，“资产负债表资产负债表”是对一时点而言的是对一时点而言的。46机会成本7.347机会成本机会成本4849问题问题50市场价格与机会成本市场价格与机会成本$25.02

24、 (Market price)$25.01 (Opportunity cost)$24.9851生产、成本理论和企业决策附录52生产函数的数值例子生产函数的数值例子Q=100 2LAQ = output;L = labor; A = land.The production function is a constant-returns-to-scale production function, a special case of the Cobb-Douglas production function.53346490600692775846316448548632705775282400490

25、5646326922453464234905486002002823464004484901412002452823163466543210123456Constant returns to scaleLaborLand543464906006927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456Diminishing marginal product of laborLaborLand826454484255346490600

26、6927758463164485486327057752824004905646326922453464234905486002002823464004484901412002452823163466543210123456Diminishing marginal product of landLaborLand5258677710156给定产量的最低要素成本组合给定产量的最低要素成本组合(1)(2)(3)(4)Input CombinationTotal costTotal costLaborLandPL=$2PL=$2LAPA=$3PA=$1A1620?B2313?C3212?D6115?57给定产量的最低要素成本组合给定产量的最低要素成本组合(1)(2)(3)(4)Input CombinationTotal cos