华农张应强微经整理

1、Chapter1 Basic Elements of Supply and Demand一、The Demand Schedule/Curve需求曲线1.The demand schedule or curve or demand denotes the relationship between price and quantity demanded ,other things being constant. 需求曲线表示的是在其他因素不变的情况下，价格和需求量之间的关系。2.Law of downward-slopping demand :when the price of a commod

2、ity is raised ,buyers tend to buy less of the commodity ,in other words ,the price and quantity are inversely related ,other things held constant. 需求曲线下降理论：当一种商品的价格升高时，购买者购买该商品的数量会减少；换句话说，当其他因素不变时，商品的需求量和价格之间成反方向变动关系。PDD'AA'B Q3.Behind the Demand CurveFactors affecting the demand curve 影响需求曲

3、线的因素（1）Average income 消费者收入水平（2）Population 消费者数量（3）Price of related goods(substitutes/complements) 相关商品的价格（4）Tastes or Preference 消费者的偏好（5）Special influence 特殊因素的影响注：当研究某一因素对需求曲线的影响时，其他因素假定不变。4.A Change in Demand and Quantity Demanded 需求的变化和需求量的变化（1）An increase in demand（需求增加的变化）：a rightward shift i

4、n the demand curve(DD') or an increase at the amount demanded at each price 需求曲线向右移动或者是每个价格上增加的需求量（2）An increase in quantity demanded（需求量增加的变化）：moving to the different point on the same demand curve after a change(AB) 在同一条曲线上移动到不同的位置上二、The Supply Schedule 供给曲线1.The supply schedule or curve or su

5、pply denotes the relationship between the price and the quantity that producers are willing to produce ,other things being constant. 供给曲线表示的是生产者在一定时期内在各种可能的价格下愿意而且能够提供出售的该种商品的数量。2.When the price of a commodity is raised ,producers tend to produce more of the commodity ,in other words ,the price and

6、quantity are positive related ,other things being constant. 当一种商品的价格上升时，生产者会趋向于生产更多的该商品。PSS'BAA'Q1 Q2 Q3.Behind the Supply CurveFactors affecting the supply curve 影响供给曲线的因素（1）The cost of production 生产的成本-the prices of inputs 投入成本-Technological advances 技术上的花费（2）Prices of substitutes 相关商品的价格（

7、3）Government policy 政府政策（4）Special influence(Eg. weather) 特殊因素的影响4.A change in supply and quantity supplied 供给的变化和供给量的变化（1）An increase in supply（供给量的增加）：a rightward shift in the supply curve(SS') or an increase at the amount supplied at each price 供给曲线向右移动或者是在每个价格上增加的供给量（2）An increase in quantit

8、y supplied（供给量的增加）： moving to a different point on the same supply curve after a price change (AB). 在同一条供给曲线上，向不同的位置移动三、Equilibrium of supply and demand 供给量和需求量之间的均衡1.Market equilibrium or equilibrium of supply and demand means that（市场均衡的含义）(1) the different forces (supply and demand) are in balance

9、 and there are no shortages or surpluses;(2) the resulting price (Pe) and quantity (Qe) align the desires of purchasers and suppliers;(3) there is no tendency for price (Pe) to rise or fall, other things being constant.（1）各参与者间的力量处于平衡状态，而且没有出现供给短缺或者数量剩余的情况（2）商品的最终价格和数量使购买者和供应商的期望达到一致（3）在其他因素不变的情况下，商

10、品的价格没有上升或者是下降的趋势。 Equilibrium with supply and demand curves:PSurplus P2PeEP1ShortageQQe2.Effect of a shift in supply or demand 供给和需求变化的影响A spell of bad weather raises the price of wheat (an ingredient of bread).So S shifts to S', and a shortage will develop at the original price (Pe).The price o

11、f bread therefore rises, encouraging production while discouraging consumption ,until quantities willingly brought and sold are equal(E'). 气象局发出坏天气的天气预报信息后，小麦的价格上升（是制作面包的一种原料），所以曲线向s移动，商品短缺情况会在原来的的均衡价格基础上发展起来，因而面包的价格会上升，鼓励生产者进行生产，但是削弱了消费者的消费欲望ShortagePS'E'SEPeQThere is an increase in ave

12、rage incomes ,so D shifts to D', and a shortage will develop at the original price (Pe).Similarly ,point E shifts to E'.SPDD'E'EPeShortageQ3.Interpreting Changes in the Equilibrium Price and Quantity 供求平衡状态的解释(1)Interpreting an increase in the equilibrium quantityD12345PSEQe'QeQ

13、(2)Interpreting an Increase in the Equilibrium PriceDS54321PPe'EPeChapter2 Applications of Supply and Demand一、Elasticity of Demand and Supply 需求和供给的弹性1.Price elasticity of demand 需求价格弹性（1）The price elasticity of demand measures how much the quantity demanded changes when its price changes. 在一定时期

14、内一种商品的需求量的变动对于该商品的价格变动的反应程度。或者说，表示在一定时期内当一种商品的需求量的价格变化百分之一时所引起的该商品的需求量变化的百分比。=(取正数） 需求量变动的百分比/价格变动的百分比（2）The size of Price Elasticity for Individual Goods 商品需求弹性范围Elasticity(>1)Inelasticity(<1)Luxuries 奢侈品 Necessaries 生活必需品Have ready substitutes in the long have no substitutes in the short run

15、run（3）Calculating Elasticities 需求弹性的计算-the Price Elasticity in an Arc需求价格的弧弹性：表示某商品需求曲线上两点之间的需求量的变动对于价格的变动的反应程度，简单地说，它表示需求曲线上两点之间的弹性。=PD:Q=Q(P)BA-Function of the Price Elasticity and the Price Elasticity at a point 需求价格的点弹性：表示需求曲线上某一点的需求量变动对于价格变动的反应程度，或者说，当需求曲线上两点之间的变化量趋于无穷小的时）E(P)=Price Elasticity

16、in Digram 价格弹性的图表Pb/kAb/2kMQOAssume a demand function is: 假设需求函数是：Q(P)=k·P+b,k,b>0,the function of the price elasticity is: E(P)=(1)When the prices decreases(AM),E(P) decreases;(2)When the price equals b/2k (at the point M),there is E(b/2k)=1(unitelastic单位弹性);(3)When the price is larger than

17、 b/2k(above point M),there is E(P)>1(elastic);(4)When the price is smaller than b/2k(below point M),there is E(P)<1(inelastic).Assume a demand function is Q=Q(P),the function of revenue is R(P)=P·R(P)R'(P)=Q+P·Q'(P)=Q·1+·Q'(P)=Q·(1E)1. When demand is inelas

18、tic(E<1),because there is R'(P)>0,a price decrease reduces revenue.价格下降减少受益2. When demand is elastic(E>1),because there is R'(P)<0,a price decrease increases revenue.价格下降增加收益3. 当需求弹性等于1的时候，价格下降对收益不产生影响The Paradox of the Bumper Harvest 丰收悖论The paradox of the bumper harvest denotes

19、 the bumper crop has lowered farmers' revenues. The reason is that the demand of food is inelastic, so large harvests tend to be associated with low revenues. 丰收悖论是指丰收反而降低了农民的收入，它的主要成因在于小麦等基本粮食作物缺乏需求弹性：消费者对于粮食这类产品的价格变动反应迟钝。粮食收成好，供给增加从而降低价格，但粮食价格降低并不会刺激需求有较大增加。于是，收成好反而使全体农民的总收益下降。解决措施：谷贱增价而入，谷贵减价

20、而出。2.Price Elasticity of Supply 供给的价格弹性（1）The price elasticity of supply measures how much the quantity supplied changes when its price changes. 表示在一定时期内一种商品的供给量变动对于该商品价格变动的反应程度，或者说，表示在一定是时期内当一种商品的价格变化的百分比之一时所引起的该商品供给量变化的百分比=（2）Application to current economic issues The economics of agricultureSSPPP

21、P1Q1Q2EQSome important technological advances in agriculture have increases supply greatly(SS').So farm prices tend to fall (P1-P2).Moreover, with price-inelastic demand, farm revenues decline.(OQEP1-OQE'P2)DEP2OImpact of a tax on price and quantity 赋税归宿1.Impact of a tax on demand and supply

22、 :A tax has no impact on demand .The supply curve shifts upward by T after raise a tax(the supply decreases).2.Calculating the incident of a tax:tax shifting to consumers :PE'PEtax shifting to producers :PEPS3.Impact of a tax on quantity and priceIn general ,the quantity decreases(QEQE'),the

23、 price consumers pay off increases(PEPE');the net price producers receive decreases(PEPS)；4.General rules on tax shifting:Generally ,the incidence of a tax depends upon the relative elasticities of demand and supply.A tax is shifting to forward to consumers if the demand is inelastic relative to

24、 supply :a tax is shifted backward to producers if supply is relatively more inelastic than demand.赋税归宿的一般原理（1）税收对供需的影响： 税收对需求没有影响。 增加税收之后供给曲线向上移动T个单位。 （供给减少）（2）赋税归属的运算 转嫁给消费者的税收是: PEPE 转嫁给生产者的税收是: PEPS （3）税收对数量和价格的影响：一般地，征税后市场均衡价格上升，均衡数量下降，消费者支付的均衡价格上升，厂商获利的均衡价格下降。 （4）赋税转嫁后的一般规律：一般地，赋税归宿取决于需求和供给者的相

25、对弹性。如果需求相对于供给缺乏弹性，则税收向前转嫁给消费者；如果供给相对于需求缺乏弹性，则税收向后转嫁给厂商。Minimum floors and maximum ceilings最低下限和最高上限The Minimum-Wage Controversy 最低工资争论_WeDMENSQ(L)QmQeQn法定工资W_Setting the minimum-wage floor at W, employment is reduced (QeQm),and unemployment increases(0QnQm).PDSS'Q(汽油量，单位加仑)（PE）2(PE)1QAQEQECeilin

26、g PriceEnergy Price ControlEAEWhen the government legislates a maximum price ceiling(PE'),the shortage occurs(QEQA) and is often managed by making people wait in line ,so there is great waste as people spend valuable time trying to secure their needs. 当政府制定一个最高上限价格（PE），商品的均衡价格就会上升，供应量无法满足需求量，商品的

27、短缺就会出现，它不得不通过使人们排队购买来解决，所以制定最高上限价格会导致人们浪费大量宝贵的时间去满足他们的需求。Chapter3 Demand And Consumer Behavior一、Utility Theory 效用理论(这是消费者理论的基础)1.Utility denotes satisfaction or how consumers rank different bundle of consumption goods ,and it indicates consumer preference.注:经济学所说的边际，就是数学中的导数。2.Marginal utility denot

28、es the additional utility arising from consumption an additional unit of a commodity. 边际效用是指消费者在一定时期内增加一单位商品的消费所得到的效用量的增量QU(Q)MU=U(Q)14-27339241013.The law of diminishing marginal utility denotes the marginal utility of that goods tends to diminish as the amount of a good consumed increases.(以喝水为例)

29、边际效用递减规律：在一定的时间内，在其他商品的消费数量保持不变的条件下，随着消费者对某种商品消费量的增加，消费者从该商品连续增加的每一消费单位中所得到的效用增量即边际效用是递减的。The Indifference Curve(无差异曲线)32123ClothingCAU3BU2U10含义：是用来表示消费者偏好相同的两种商品的所有组合，或者说，它表示能够给消费者带来相同的效用水平或满足程度的两种商品的所有组合1.The points(A,B,) on the indifference curve(U1) represent consumption bundles among which the

30、consumer preference is indifferent. 无差异曲线上的每一点的效用都是相同的2.As we increase both goods and thus move in a northeasterly direction across the map ,we are crossing successive indifference curves；hence ,we are reaching higher and higher level of utility.不同曲线离原点越远，效用越大，偏好越大3.Indifference curve are convex to

31、the origin property (凸向原点)is called the law of substitution.替代规律：无差异曲线是凸向原点的，即向右下方倾斜，曲线的斜率为负值(1)Marginal rates of substitution(MRS)边际替代率（在维持效用水平不变的前提下，消费者增加一单位某种商品的消费数量时所需要放弃的另一种商品的消费数量）equal the absolute slope of the indifference curve. F0MRSFC=- limc/F=-dC/dF(2)MRS are the measure of the goods'

32、; relative marginal utilities:U1=U(F,C)0=U/F·dF+U/C·dC=MUF/MUCU/CU/FMRSFC=(3)The law of substitution(the law of diminishing marginal rates of substitution) denotes its MRS diminishing as more and more of a good(F) is consumed(AB).边际替代递减规律：在维持效用水平不变的前提下，随着一种商品数量的连续增加，消费者为得到每一单位的这种商品所需要放弃的另一

33、种商品的消费数量是递减的。Consumer Equilibrium消费者平衡Budget Line预算线（预算约束线、消费可能线和价格线）：预算线是指在消费者收入和商品价格既定的情况下，消费者的全部收入所能购买到的两种商品不同数量的各种组合。ClothingI/PCCAMA BFoodPF·F+PC·C=INI/PFOAssume the consumer's income is I, the price of food is PF and the clothing is PC.MN is the consumer's budget line .It sum

34、s up all the possible combinations of the two goods that would exhaust the consumer's income. Its absolute slope equals the PF/PC ratio.The Equilibrium Position of Tangency(tan)切点的均衡位置PF/PC=MRSFC=MUF/MUCClothingI/PCCFoodOU3U2U1MFI/PFI/PFI/PCNBBAssume the utility function is :U=U(F,C),the budget

35、line is :PF·F+PC·C=I.1.Geometrical Analysis of Consumer EquilibriumThe consumer is free to move anywhere along the budget line NM. He will move to that point(B) which yields the greatest utility. Geometrically, the consumer is at equilibrium where the slope of the budget line(=PF/PC) equal

36、s the MRSFC(=MUF/MUC):PF/PC=MUF/MUC2.Mathematical Analysis of Consumer EquilibriumS.t:PF·F+PC·C=Ithe Lagrange function(拉格朗日函数):L(F,C,)=U(F,C)+(PF·F+PC·C-I) is the Lagrange multiplier(拉格朗日常数)L'F=MUF+PF=0L'C=MUC+PC=0L'=PF·F+PC·C-I=0MUF/PF=MUC/PC=MU/P=K(constan

37、t常数)3.Equi-marginal Principle 等边际原则MUF/PF=MUC/PCThe fundamental condition of maximum utility is the equimarginal principle. It states that a consumer having a fixed income and facing given market prices of goods will achieve maximum utility when the marginal utility of the last dollar spent on each

38、good is exactly as same as the marginal utility of the last dollar spent on any other goods.效用最大化的基本条件是等边际原则。它表示，在一定的预算约束下，为了实现最大的效用，消费者应该选择最优商品组合，使得两商品的边际替代率等于两商品的价格之比。也可以这样理解，在消费者均衡点上，消费者愿意用一单位的某种商品去交换的另一种商品的数量，应该等于该消费者能够在市场上用一单位的这种商品去交换得到的另一种商品的数量4.Why Demand Curve Slopes Downward 需求曲线斜率下降In gene

39、ral, we hold the marginal utility per dollar constant. Therefore, according to the equimarginal principle, a higher price for a good reduced the consumer's desired consumption of that commodity; this shows why demand curves slop downward.一般地，我们假定收入的每一美元带来的边际效用不变。因此，根据等边际原则，某种商品价格上升，会减少消费者对该商品的消费

40、，这就证明了为什么需求曲线向下倾斜。（等边际原则是指导我们消费的基本原则）。Single Price Change and Deriving the Demand CurveS.t.PF·F+PC·C=IclothingOI/PCBMFoodMaxU=U(F,C)NBU2MFBI/PFFBPPFPFOFBFBFoodDAssume tastes as represented by the indifference curves remain unchanged, and the price of clothing and the consumer's income

41、stay constant. As we increase the price of food(PFPF'),the budget line has pivoted on point N inward(绕N向内旋转) and is now NM'. The new tangency equilibrium is at B', with less food(FBFB').Thus, we decline a neat downward-slopping demand curve from indifference curves.课堂练习已知某消费者每年用于商品1和

42、商品2的收入为540元，两商品价格分别为P1=20和P2=30元，两商品消费量分别为x1和x2,该消费者效用函数为U(x1,x2)=3x1·x22,求(1)该消费者购买这两种商品的最优数量;S.t.20x1+30x2=540MaxU(x1,x2)=3x1x22L(x1,x2,)=3x1x22+(20x1+30x2-540)L'x1=3x22+·20=0L'x2=6x1x2+·300L'=20x1+30x2-5400x1=9 x2=12(2)消费者对商品1的需求函数;S.t.P1X1+30X2=540MaxU(x1,x2)=3x1x22L(x

43、1,x2,)=3x1x22+(P1X1+30x2-540)L'x1=3x22+·P1=0L'x2=6x1x2+·300L'=P1X1+30x2-5400x1=180/P1(3)证明商品1具有不变的需求弹性。P1X1= -·X1= -180/P1·(-180/P12)=1P E(P1)The Paradox of Value价值悖论The paradox of value: how is it that water, which is essential to life, has little value(price),while

44、diamonds, which are generally used for conspicuous consumption, command an exalted value?MUF/PF=MUC/PC=MU/P=K(constant常数)P=MU/KIn general, we hold the marginal utility per dollar of income constant. Therefore, according to equimarginal principle, we can derive “P=MU/K” from “MU/P=K”. It indicates th

45、at water's price(value) is not determined by its total utility but its marginal utility. Because there is so much water, the large quantity pulls utility so far down and thus reduces its price.价值悖论是这么一种现象，水是生命所必须的，但它的价格很低，而钻石，一般用作装饰物，它的价值又那么高？ 一般地，我们假设收入中的每一美元带来的边际效用不变，因此，根据等边际原则（MUF/PF= MUc /PC

46、） ，我们从公式MU/P=K（contant）可以推导出P=MU/K，这表明水的价格并不是取决于水的总效用而是边际效用。因为有着大量的水，使得水的边际效用大大地降低，从而大大降低水的价值（价格）。Consumer Surplus 消费者剩余Consumer surplus measures the extra utility that consumers receive over what they pay for a commodity.消费者剩余：消费者剩余是一种物品的总效用与其市场价值之间的差额，它衡量的是消费者从某一物品的购买中所得到的超过他们为之支付的那部分额外效用。PSEDQQ1O

47、P1Chapter4 Theory of ProductionBasic Concepts1.The Production Function 生产函数：表示在一定时期内，在一定的技术条件下，生产中所使用的各种生产要素的数量与所能生产的最大产量之间的关系The production function specifies the maximum output that can be produced with a given quantity of outputs. It is defined for a given state of engineer and technical knowledg

48、e:(1)Our discussion assumes that business always strive to produce efficiency or attempt to a maximum level of output for a given close of inputs.(2)When technology changes, the production function also changes.2.Total, Average and Marginal Product 总产量 平均产量 边际产量Total product designates the total amo

49、unt of output in every physical unit(实物单位)APL=Q/LAverage product equals total output divided by total units of input.MPL=Q/L=QLThe marginal product of an input is the extra output added by one extra unit of that input while other inputs are held constant.3.边际报酬递减规律（短期生产的一条基本规律）：在技术水平不变的条件下，在连续等量的把某一

50、种可变的生产要素增加到其他一种或几种数量不变的生产要素上去的过程中，当这种可变生产要素的投入量小于某一特定值时，增加该要素投入所带来的边际产量是递增的；当这种可变生产要素的投入量连续增加并超过这个特定值时，增加该要素的投入所带来的边际产量是递减的。（1）TP(L)=MP(L)>0，TP(L)是增加的（2）TP(L)=MP(L)<0，MP(L)是递减的，TP曲线是凹的（3）TP(L)=MP(L)>0，MP(L)是凸的（凸向原点）4.规模报酬（1）规模报酬不变：产量增加的比例等于各种生产要素增加的比例（2）规模报酬递增：产量增加的比例大于各种生产要素增加的比例（3）规模报酬递减：

51、产量增加的比例小于各种生产要素增加的比例第五章 成本的分析一、从短期和长期来分析成本在短期内，固定成本是不可以改变的，可变成本是可以改变的。在长期内，固定陈本是可以改变的，所以一切成本都是可以改变的1.固定成本（1）代表的是生产的总费用（2）不受生产产量变化的影响（3）包括了租用厂地的租金利息2.可变成本：是指随着生产产量的变化而变化的成本3.总成本：生产一定数量的产品对全部生产要素所支出的总成本二、边际成本和U型边际成本曲线1.边际成本：指生产额外一单位产品所需增加的成本。从定义出发，我们可以发现，边际成本等于总成本曲线或变动成本曲线上的点的斜率2.一条U型曲线是由先递增后递减的边际产量决定的。在短期内，当