第7章 成本分析 萨缪尔逊《经济学第十八版微观经济学 (浙江财经学院)》》ppt课件.ppt

1,成本分析,第7章,2,成本的经济分析,7.1,3,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.,4,固定成本,The cost related to fixed factors is called fixed cost (固定成本，不变成本).A firms fixed costs, sometimes called “overhead” (企业一般管理费用) or “sunk costs” (沉入成本), must be paid even if the firm produces no output, and they will not change if output changes.,5,变动成本,The cost related to variable factors is called variable cost (变动成本，可变成本).Variable costs are those which vary as output changes. By definition, VC begins at zero when q is zero.,6,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：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，目的是为了让函数关系具有唯一性。,7,Totalcost,in short run:,in long run:,Totalcost,Variablecost,=,8,9,边际成本,The concept of marginal cost is one of the most essential in microeconomics. Marginal cost (MC) denotes the extra or additional cost of producing 1 extra unit of output.,10,For 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.,11,边际成本的计算,30,25,20,30,50,12,利用变动成本计算边际成本,30,25,20,30,50,13,MC = TCq+1 TCq,= (VCq+1FC) (VCqFC),= VCq+1 VCq,数学推导,为什么可以用变动成本来计算边际成本：,14,总成本和边际成本的关系,Output,Total cost,Output,Marginal cost,15,平均成本,Average cost(or unit cost),=,total cost,output,=,TC,q,=,AC,Averagefixed cost,=,fixed cost,output,=,FC,q,=,AFC,Averagevariable cost,=,variable cost,output,=,VC,q,=,AVC,16,总成本、固定成本和变动成本,Total cost,Variable cost,Fixed cost,Quantity,Cost,17,平均成本和边际成本,Quantity,Average and marginal cost,MC,AC,AVC,AFC,18,平均成本与边际成本的关系,成本,产量,边际成本,平均成本,平均成本最低点,边际成本曲线自下而上穿越平均成本曲线的最低点。,19,平均成本边际成本,成本,产量,边际成本,平均成本,边际成本平均成本,平均成本随着产量增加而向下。,16元,22,12元,20,平均成本边际成本,成本,产量,边际成本,平均成本,17元,边际成本 平均成本,平均成本随着产量增加而向上。,23元,50,21,边际成本和平均成本的关系,ACq+1,=,ACqqMC,q1,=,ACq(q1) MCACq,q1,= ACq,MCACq,q1,22,小结,If MCAC, then AC is rising.If MC=AC, then AC is at its low point.If MCAC, then AC is falling.,Quantity,AC and MC,AC,23,边际成本和平均变动成本的关系,AVCq+1,=,AVCqqMC,q1,=,AVCq(q1) MCAVCq,q1,= AVCq,MCAVCq,q1,24,小结,If MCAVC, then AVC is rising.If MC=AVC, then AVC is at its low point.If MCAVC, then AVC is falling.,Quantity,AC and MC,AVC,25,斜率和边际成本的关系,Tangent line,Total cost curve,1 unit of output,Marginal cost,a,26,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.,27,85,210,28,报酬递减和U形成本曲线,Labor,Marginal product of labor,Marginal cost,Output,A,B,D,A,B,D,MC,AC,In the short run:,29,最小成本规则,To a given output:,Marginal product of input A,Price of input A,=,Marginal product of input B,Price of input B,=,30,等边际原理,This gives you the marginal product per dollar of output.,Equimarginal Principle,31,替代规则,If the price of one factor falls while all other factor prices remain the same, firms will profit by substituting the now-cheaper factor for all the other factors.,MP of Labor,Price of Labor,=,MP of Capital,Price of Capital,32,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。,33,短期成本与长期成本的关系,成本,产量,长期平均成本,1 亩地更有利,2 亩地更有利,3 亩地更有利,4 亩地更有利,34,规模经济与规模不经济,成本,产量,长期平均成本,规模经济,规模不经济,35,经济成本和企业会计,7.2,36,经济成本和会计成本,经济成本（economic cost）：投入生产的所有资源的机会成本。会计成本（accounting cost）：按照会计规则计算的成本在会计帐面上显示出来的经济成本称为外显（显性）成本（explicit costs），在会计帐面上不能显示出来的经济成本称为内含（隐性）成本（implicit costs）。,37,经济利润,经济成本 = 外显成本 + 内含成本 = 机会成本经济利润 = 销售收入 经济成本经济利润是计入了所有使用的资源代价后的纯收益。,38,一个体饭馆业主使用自己的店面， 1年盈利3万元，这个3万元称之为会计利润。,若不开饭馆，在所有可选工作中最高可赚得2万元，人力的经济成本就是2万元。如果店面用于出租可以获得1.5万元租金，那么店面的经济成本就是1.5 万元。,考虑到经济成本后，这个个体饭馆业主的经济利润为0.5 万元。,39,收益表,40,收益表,41,The depreciation is taken in annual accounting charges over the assets accounting lifetime,折旧,$10,000,$10,000,$10,000,$10,000,$10,000,$10,000,$10,000,$10,000,$10,000,$10,000,depreciation = the capital goods historical cost or purchase price.,42,资产负债表,43,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 worth,44,例子,Suppose 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.,45,会计惯例,The value placed on almost every item reflects its historical costs.,46,说明,“收入表”是描述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刻，企业的资产、负债和所有者权益状况。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。,47,机会成本,7.3,48,机会成本,The opportunity cost (机会成本) is the value of the good and service forgone (放弃).The opportunity cost includes all consequences (结果), whether they reflect explicit monetary transactions (货币交易) or not.,49,The immediate dollar cost of going to a movie instead of reading your economics textbook is the price of the movie ticket.,The opportunity cost also includes the possibility of gaining a better understanding of microeconomics and therefore becoming more successful in business.,50,问题,Why do the students watch more TV the week after exams than the week before exams?,51,市场价格与机会成本,在一个良好运行的市场上，价格等于机会成本。,$25.02 (Market price)$25.01 (Opportunity cost)$24.98,52,生产、成本理论和企业决策,附录,53,生产函数的数值例子,Q=100 2LA,Q = 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.,54,Constant returns to scale,Labor,Land,55,Diminishing marginal product of labor,Labor,Land,56,Diminishing marginal product of land,Labor,Land,57,给定产量的最低要素成本组合,58,给定产量的最低要素成本组合,59,等产量曲线,Labor,Land,60,Land,Labor,A,B,C,D,q,Equal-product curve or isoquant,There are an infinite number of equal-product contour lines (等值线) in the map.,61,Land,Labor,A,B,D,q,MN: AMPA=L MPL,替代率,62,等成本线,Land,Labor,Labor price = $2, Land price = $3,TC=$3,TC=$6,TC=$9,TC=$12,TC=$15,TC=$18,equal-cost Line:,63,Land,Labor,TC=$3,TC=$6,TC=$9,TC=$12,TC=$15,equal-cost Line:,APA=L PL,替代率,64,最低成本投入组合,Land,Labor,TC=$3,TC=$6,TC=$9,TC=$12,A,B,C,D,65,最低成本条件,EQUIMARGINAL PRINCIPLE,66,说明,等产量线方法一般用于企业的长期行为分析，因为对于长期来说，所有的生产要素都可以改变，所以可以在等产量线上进行选择。对于短期分析而言，按惯例一般不使用等产量线分析方法。,67,End Of Lesson,