经原学习重点和难点.docx

1、经原学习重点和难点小注一下1 这是04级师兄师姐在大一学习经济学原理的过程中自行总结归纳的一份材料，重难点都只是当时的个人取舍，不一定是test point。2 图对于经原学习是极其重要的，但是由于作者不擅电脑绘图，这里没有配图，希望大家平时要多多动手画图哦！3 文中提到的“英文Pxx”指英文版教材页码，“中文”指中文版。“新编”指由盛晓白，黄健康主编，北京大学出版社出版的微观经济学新编，是作者在学习微观时使用的参考书。个人觉得挺好4 由于作者水平有限，时间仓促，难免有错误和漏洞，希望大家可以多多指教最后，希望大家学经原学得开心。_。Chapter3 basic elements of sup

2、ply and demandTheory of supply and demandShows how consumer preferences（偏好） determine consumer demand for commodities, while business costs are the foundation of the supply of commodities.（商品）Competitive（竞争的） equilibrium（均衡）The demand curves and the supply curves intersect（交叉）the forces of demand an

3、d supply are just in balance.DEMANDThe demand schedule (the demand curve)The relationship between price and quantity bought. Demand curveThe graphical（图示的） representation of the demand scheduleLaw of downward-sloping demand 需求向下倾斜规律When the price of a commodity is raised (and other things are held c

4、onstant), buyers tend to buy less of the commodity.Substitution effectWhen the price of a good rises, people will substitute other similar goods for it.Income effectWhen a price goes up, people find themselves somewhat poorer than they were before. They have in effect less real income.Market demandR

5、epresents the sum total of all individual demandsA array of factors that influences how much will be demanded at a given pricedetermines the market demand:1. Objective elements:1.1 Average levels of income: people tend to buy more of almost everything when their incomes rise, even if prices dont cha

6、nge.1.2 Size of the market: measured by population, 10 people tend to buy more than 1 people.1.3 The prices and availability of related goods: demand for oil tends to be low if the price of natural gas is low. (substitute product)2. Subjective（主观的） elements:2.1 Tastes2.2 Preferences3. Special influe

7、nces: the demand for umbrellas is high in rainy city but low in sunny city. Expectations about future economic conditions, particularly pricesSUPPLYThe supply schedule (or supply curve) for a commodityShows the relationship between its market price and the amount of that commodity that producers are

8、 willing to produce and sell, other things held constant.Elements that affect the supply curve:1. Cost of productionOne major element underlying the supply curve, which is primarily determined by the prices of inputs and technological advances2. The prices of related goods3. Government policy4. Spec

9、ial influences (weather influences farming.Shifts in supply When price of a good changes, producers change their production and quantity suppliedmove along the curve, but the supply and the supply curve do not shift. When other influences affecting supply change, supply changes and the supply curves

10、 shifts.Supply increases (or decreases) when the amount supplied increases (or decreases) at each market price.EQUILIBRIUM OF SUPPLY AND DEMANDMarket equilibriumComes at that price and quantity where the forces of supply and demand are in balance.The equilibrium price is also called the market-clear

11、ing price(市场出清价格)There are no shortages or surpluses（剩余） at the equilibrium price.What the market mechanism（结构） accomplishes（实现）rationing （限量）by prices (rationing by the purse)What goods are produced?For whom are goods produced?How to produce?WORDSIndividual commodities 单个商品Market mechanism 市场机制PART

12、 TWO MICROECONOMICS: SUPPLY, DEMAND, AND PRODUCT MARKETSChapter4 applications of supply and demandELASTICITY OF DEMAND AND SUPPLY1. Price elasticity of demand (price elasticity)Measures how much the quantity demanded of a good changes when its price changes.The percentage change in quantity demanded

13、 divided by the percentage change in priceElasticityFactor 1Factor 2Factor 3ElasticLuxuriesHave substitutesHave more time to adjustInelasticNecessitiesHave no substitutesHave less time to adjust*factor3: the length of time that people have respond to price changesPlus:4. 支出占消费者收入比重小的商品需求价格弹性小；占比重大的商

14、品需求价格弹性大。5. 数量越大，价格越低的商品价格弹性小；数量越小，价格越高的商品价格弹性大。Calculating elasticitiesPrice elasticity of demand =ED=percentage change in quantity demanded/percentage change in price Price-elastic demand:A 1 percent change in price calls forth more than a 1 percent change in quantity demanded. Price-inelastic dem

15、andA 1 percent change in price evokes（引起） less than a 1 percent change in quantity demanded. Unit-elastic demandThe percentage change in quantity is exactly the same as the percentage change in price.This condition implies that total expenditures on the commodity (equal P*Q) stay the same even when

16、the price changes.Three key steps to calculate (*1) 计算需求曲线的价格弹性：直线上任何一点的弹性等于位于该点之下的线段长度与位于该点之上的线段长度的比值。Polar（极） extremesthe price elasticities are infinite or zerocompletely elastic and completely inelastic Completely inelastic demand (with zero elasticity): the quantity demanded responds not at all

17、 to price changes. (Vertical （垂直的）demand curve)需求量不随价格而变动 Infinitely（无限的） elastic demand: a tiny change in price will lead to an indefinitely large change in quantity demanded. (Horizontal demand curve)价格一定，需求量可以是无限的Warning: elasticity is not the same as slope. (*2)一般来说，在任何直线的中点M的上方，需求富有弹性，ED1；中点处，需

18、求具有单位弹性ED1；中点以下，需求缺乏弹性ED1。Elasticity and revenue（收入）Total revenue: price times quantity When demand is price-inelastic a price decrease deduces total revenue. When demand is price-elastic, a price decease increases total revenue. In the borderline case of unit-elastic demand, a price decrease leads

19、to no change in total revenue.2. Price elasticity of supplyThe responsiveness（快速反应） of the quantity supplied of a good to its market priceThe percentage change in quantity supplied divided by the percentage change in priceFactors that determine supply elasticity:1. The ease with which production in

20、the industry can be increased 行业中增加生产的困难程度 Whether all the inputs can be readily found at going market prices 纺织行业，价格的微小上升就会导致产出大幅度增加 Whether the production capacity is severely limited 南非金矿开采，即使黄金价格急剧上升，产量也只能增加少许2. The time period under consideration 供给者做出反应时间的长短 给定的价格变动会对供给量产生较大的影响。价格上升后的短暂时期内，企业也

21、许无法增加其劳动、物资和资本投入，因此供给可能缺乏弹性；随着时间推移，企业可以雇佣更多工人，建造新的厂房和扩大生产能力供给弹性变大。BBBAPPLICATIONS TO CURRENT ECONOMIC ISSUESLong-run relative decline of farming 农业的长期相对衰落Sharp increases in supply outpaced modest increases in demand, producing a downward trend in farm prices relative to other prices in the economy.M

22、any governments attempt to help farmers by reducing their production.Production restrictions (限制生产) are typical of government market interferences that raise the incomes of one group at the expense of others. This kind of policy is inefficient: the gain to farmers is actually less than the harm to c

23、onsumers.Incidence (归宿)The ultimate economic impact or burden of a tax (税赋的最终经济影响)Who bears the true burden of a tax?general rules on tax shifting (税收转嫁的一般原理)The incidence of a tax is determined by the effect on prices and quantities in supply-and-demand equilibrium.In general, the burden or inciden

24、ce depends upon the relative elasticities of demand and supply.A tax is shifted forward to consumers if the demand is inelastic relative to supply.A tax is shifted backward to producers if supply is relatively more inelastic than demand.汽油的需求相对于供给缺乏弹性，则赋税的负担大部分转嫁给了消费者。土地的供给相对于需求缺乏弹性，则税赋大部分转嫁给了供给者。注：

25、汽油的例子需求曲线没有移动，因为汽油税增加后在每一个零售价格水平上，需求量并没有变化。供给曲线向上移动，因为只有当生产者得到与以前相等的净价格（the same net price），他们才会愿意出售某个数量。在每一供给量上，市场价格上升的幅度必须正好等于税额。Subsidies (补贴)Taxes are used to discourage consumption of a commodity-gasoline. Subsidies are used to encourage production-agriculture.Governments occasionally interfere

26、 with the workings of competitive markets by setting maximum ceilings or minimum floors on prices. In such situations, quantity supplied need no longer equal quantity demanded.Ceilings lead to excess demand ( price controls produce shortages in the case of gasoline.Floors lead to excess supply.The i

27、nterference may raise the incomes of a particular group (farmers or low-skilled workers), but often distortions and inefficiencies results. Waste, inefficiency, and aggravation(短缺) are certain companions of such interferences.WORDSProduct markets 产品市场Chapter 5 demand and consumer behavior Economics

28、relies on the fundamental premise that people tend to choose those goods and services they value most highly.UtilityDenotes satisfaction, refers to how consumers rank different goods and services In the theory of demand, we say that people maximize their utility, which means that they choose the bun

29、dle of consumption goods that they most prefer.Marginal utilityDenotes the additional utility arising from consumption of an additional unit of a commodity消费新增一单位商品时所带来的新增的效用Law of diminishing marginal utilityStates that the amount of extra or marginal utility declines as a person consumes more and

30、more of a good效用的单位是“尤特尔”( utils )边际效用曲线必然向下倾斜；总效用曲线必然为反U形。总效用是从开始处累计起来的所有边际效用之和。图：边际效用曲线之下的总面积等于消费单位数相同的总效用曲线的高度。Equimarginal principle: equal marginal utilities per dollar for every goodEquimarginal principle等边际准则: The fundamental condition of maximum satisfaction or utilityThe fundamental conditi

31、on of consumer equilibrium 消费者均衡的基本条件It states that a consumer having a fixed income and facing given market prices of goods will achieve maximum satisfaction or utility when the marginal utility of the last dollar spent on each good is exactly the same as the marginal utility of the last dollar spe

32、nt on any other good. 花费在任何一种物品上的最后一美元所得到的边际效用正好等于花费在其他任何一种物品上的最后一美元所得到的边际效用时，该消费者得到最大的满足或效用。Marginal utility of income收入的边际效用:The common marginal utility per dollar of all commodities in consumer equilibrium消费者均衡时，各种物品每一美元的一般边际效用MUgood1/P1 = MUgood2/P2 = = MU per $ of income Why demand curves slope dow