AP微观经济梳理

济宁孔子国际学校AP 微观经济学知识点梳理 I. Basic Economic Concepts 经济学基础概念 (814%) 选择A.Scarcity, choice and opportunity cost 稀缺性（概念），选择（概念），机会成本（计算）a. Scarcity(Unlimited want vs. Limited resources )Make choices Economicsb. Opportunity cost (The best choice you give up) include explicit and implicit cost, the slope公式：Opportunity Cost of doing A=loss in B / gain in Ac. Factors of productions are resources.B. Production possibilities curve 生产可能性边界曲线（识图，计算）横纵坐标轴分别是两种产品的产量，斜率是机会成本。a. 曲线弯: law of increasing opportunity cost（生产鞋和电脑的资源不可相互替代）；because the resources are not perfectly adaptable.b. 直的: 生产两种物品的资源可完全替代，也就是说资源完全可以通用，机会成本恒定。C.Comparative advantage, absolute advantage, specialization and trade 比较优势（计算），绝对优势（计算），专业化（概念），贸易（概念）a. 绝对优势：more productive. 生产一单位less time or less input。（或者单位time或input生产更多）如果给的是时间，则不用换算b. 比较优势：lower opportunity cost. xxx/hour 别忘了是与本国生产另一产品的opportunity cost 相比较c. Specialization and trade can increase productivity and output. Economic growth could be achieved by: Increase in the quantity of resources Increase in the quality of existing resources Technological advancementsd. Trade can be good to both countries even if one country has the absolute advantage in all products. Two countries trade only when they have comparative advantage on different good. After trading, countries gain more production at lower cost.D.Economic systems, Property rights and the role of incentives计划经济和市场经济（概念），产权（概念），激励的作用（概念）Command economy:公平equitable，government determines，but sophisticated to allocate properly, lack of incentives for innovation; Free/capitalism economy: private ownership, property rights, free, incentives, competition,供求决定价格，市场决定生产多少消费多少。如果是mixed economy，则market和government共同决定。F. Marginal analysis 边际思维（概念）MBMC, 做这件事。Marginal=additionalII. The Nature and Functions of Product Markets 产品市场的特点和功能 (5570%) A. Supply and demand 供给和需求 (1520%)1. Market equilibrium 市场均衡 （先Q后P）Equilibrium quantity 由 Qs 和Qd决定：Qs=QdD 的变动才会引起P的变动2. Determinants of supply and demand 供给和需求的影响因素影响需求 影响供给TasteTax /SubsidyCost of inputIncomeTechnologyPrice of substitute good Price of complement goodTaxExpectation of pricecost of inputstechnology and productivitySubsidy/taxExpectation of pricePrice of other goods切记：Price变动导致沿着曲线的移动，而不是曲线本身的移动；上表里的因素都是导致曲线本身移动的。S,D同向移动：左（Q减少，P不定）；右（Q增加，P不定）S,D反向移动：内（P增加，Q不定）；外（P减少，Q不定）3. Price control Price ceiling: Creates shortageprice floor：最低工资是经典例子Creates surplus increase deadweight lossWelfare Analysis=consumer surplus+ producer surplusThe market is efficient only when MB=MC, or total welfare is maximized.4. Elasticity弹性a. Price elasticity of demandEd=(%change in quantity demanded of good x)/(%change in the price of good X)b. Price elasticity of supply一定要分清问的是关于supply还是demand需求和供给价格弹性算绝对值，不关心正负号；弹性为无穷时，叫Perfectly Elastic完全弹性，弹性大于1时，叫Relatively Elastic，弹性等于1时，叫Unit elastic，弹性小于1时，叫relatively inelastic，弹性等于0时，perfectly inelastic完全刚性。应用：弹性为elastic时，P降低，Total Revenue会增加，因为Q增加的程度大于P降低的程度；为inelastic时，P降低，Total Revenue会减少，因为Q增加的程度小于P降低的程度。影响价格弹性的因素：奢侈品的弹性大于1，必需品的弹性小于1；时间长弹性大于1；替代品多弹性大于1；占收入比重大弹性大于1。c. Income elasticity of demandEI=(%change in quantity demanded of good X)/(%change in income) 需求收入弹性正号表示物品是normal goods，负号表示inferior goodsd. Cross-price elasticity of demandEx,y=(%change in quantity demand of good X)/(%change in price good Y)交叉需求弹性正号表示A和B为substitution，负号表示A和B为complementary。5. Consumer surplus, producer surplus and market efficiency剩余和市场效率消费者剩余=支付意愿市场价格；生产者剩余=市场价格生产成本Market efficiency： MB=MC, Total Surplus最大Supply do the same（longer time, more elastic）6. Tax incidence and deadweight loss税收负担和无谓损失1.monopolyPerfectly competitive marketPer-unit subsidy/taxMC&ATC both changeOnly ATC changeLump-sum subsidy/taxNothing changeNothing change2.Tax 永远是向sellers 收的，只是sellers根据elasticity of demand and supply 的不同来向consumer收钱。3.Tax or subsidy/negative, positive externality会造成deadweight loss, but shift of supply or demand curve 不会，因为它们形成了新的均衡点。4.收税之后，suppliers & demanders charge different money.(one below, one above)5.在画deadweight loss的时候，尖点永远是optimal pointTrade BarriersImport when world price is lower. Export when world price is higher.Create deadweight lossTR of government=quantity imported/exported x the tariffC. Theory of consumer choice 消费者选择理论 (510%) 可能大题1. Total utility and marginal utility 总效用和边际效用Utility is the satisfaction or happinesslaw of diminishing marginal utility 2. Utility maximization: equalizing marginal utility per dollar边际效用之比等于价格之比MU1/MU2 =P1/P2，在预算允许的条件下。3. Income and substitution effects收入效应，替代效应Income effect：normal: 都多买或少买substitution effect：normal: 一个多买一个少买inferior: income decrease 多买，price increase 少买 D. Production and costs生产与成本 (1015%)1. Production functions: short and long run短期和长期的生产函数Short run: only labor variableLong run: all variable2. Marginal product and diminishing returns边际产量和边际产量递减规律MP of A= additional output/ additional input of AMarginal returns start diminishing when MP decreases as L increasesFC不变随着labor的增加，MC增加（因为生产力下降）MC和MP的图！3.Short-run costs短期成本曲线MC曲线最后是上扬的，是因为，生产能力全部被利用之后，再增加边际投入，就会出现边际产量递减，边际成本递增。4. Long-run costs and economies of scale长期成本曲线和规模经济长期有economies of scale规模经济，指随着产量增加ATC不断下降，反之则是diseconomies of scale规模不经济, constant returns to scale规模收益不变指产量变动而ATC不变，或者说投入增加的倍数与产出增加的倍数相同。规模经济的产生是因为specialization& ability to purchase5. Cost minimizing input combination成本最小化的要素组合MPL/PL=MPK/PKE. Firm behavior and market structure企业行为和产业组织 (2535%) 必出大题1. Profit利润a. Accounting profit，economic profit会计利润（总收益-显性成本）和经济利润（总收益-显性成本-隐性成本）b. Normal profit指的经济利润为0（但依然赚着会计利润）d. Profit maximization对各种类型的企业都适用的利润最大化条件是当MR=MC时的产量，即使没有恰好相等的点，也要选择MR刚刚大于MC的那个产量。2. Perfect competition完全竞争Price taker No economic profit in the long runa. Profit maximizationP=AR是恒等式，因为P=TR/Q,AR=TR/Q。完全竞争市场很特别，企业获得利润最大化的产量是在P=MC=MR=AR时。b. Short-run supply and shutdown decision短期的企业供给曲线是MC曲线在AVC上方的那段；在短期，如果PMRc. Inefficiency of monopoly 垄断无效率因为产量少于需求并且收取高于期望的价格，所以垄断是效率低的。too little of the production and charges too high a price.会画图：知道Revenue maximizing（MR=0的产量），profit maximizing（MR=MC）, efficient maximizing（P=MC）与fair return企业经济利润为0（ATC和D相交）这四种情况下的产量和价格。d. Price discrimination 价格歧视1.consumer surplus=02.produce at allocative efficient point3.be able to separate buyers and block them from retailing.4. Monopolistic competition垄断竞争a.Product differentiation and role of advertising有许多卖者，每个卖者提供略有差别的产品，无壁垒，有决定价格的能力，做广告的必要性b.Profit maximization与垄断类似。先通过MR=MC的条件确定产量Q，再通过需求曲线找到对应的P，这是垄断竞争企业利润最大化的条件。P=ARMR。c.Short-run and long-run equilibrium短期有profit或loss，吸引新企业进入或旧企业退出市场。进而达到长期均衡，D与ATC曲线相切，切点刚好是MC=MR投影到D的点，长期利润为0。因为在ATC的下降部分相切，所以有规模经济。d.Excess capacity and inefficiency垄断竞争无效率体现在：产能过剩 Excess capacity，价格过高 PMC5. Oligopoly 寡头a.Interdependence, collusion and cartels卡特尔、联盟、互赖受反托拉斯法的约束，有market power，企业数量很少；合作的话，如同垄断一般获利最大，如果不合作，则利润不高。b.Game theory and strategic behavior会利用支付矩阵分析占优策略。必考。题目中可能一方有占优策略另一方无占优策略，那么没有的那方要先揣测出有占优的那方的意图。F. Factor Markets要素市场. (1018%) 出大题1. Derived factor demand派生需求对一种生产要素的需求来自（派生自）对另一种产品的需求。D for productprice of productMRPLhiring of labor at the current wage2. Marginal revenue product边际产量值增加一单位劳力所引起的产值的变化 MRP=MP*MR=MP*P (perfectly competitive market)3. Labor market and firms hiring of labor (perfectly competitive market)D=MRP曲线，MRP=P*MPL S=wage利润最大化雇用人数：w=VMP=MRP=P*MP窍门：a. 影响需求1. product demand2. productivityTechnical progressQuantity of other resourcesquality of variable resources3. prices of other resourcesSubstitute resourcesSubstitution effectIncome effectComplementary resourcesb. 影响供给changes in tastewomen workspeople who rely parents increasechanges in other opportunitiesimmigration(Monopsony)Quantity is hired when MC=MRPPrice=SupplyG. Market Failure and the Role of Government市场失灵和政府管制 (1218%)1. Externalities外部性，出大题a.Marginal social benefit and marginal social costb.Positive externalities正外部性：MSBMSC under allocation subsidy(per unit) lump sum subsidy has no effect on the graph.c.Negative externalities负外部性：MSBMSC over allocation tax2. Public goods公共物品excludablenonexcludableRivalPrivate goodsCommon resourcesnonrivalNatural monopoly goodsPublic goods3. Public policy to promote competitiona.Antitrust policycompetitionb.Regulation政府对垄断的管制如果政府给垄断、垄断竞争、完全竞争企业一次性补贴或一次性征税（lump sum subsidy or tax），不会对企业的MC产生影响，因此不会影响利润最大化产量和价格。但由于影响了ATC，导致利润或loss有变化。如果征税或补贴是按单位per unit，则会影响MC，继而影响利润最大化产量和价格。4. Income distribution促进市场竞争的政策a.Equity认识洛伦兹曲线：是反映收入不平等程度的。基尼系数是不规则图形面积比上大三角面积，越小越接近公平。b.Sources of income inequality收入不平等的来源：歧视，教育程度不同，能力不同，动机不同。必背定义 ScarcityLaw of increasing costProductive efficiency Allocative efficiencyMarginal utilityThe change in total utility that results from a one-unit increase in the quantity of a good or service consumed.law of diminishing marginal utility The general tendency for marginal utility to decrease as the quantity of a good consumed increases.Marginal productThe change in total product that results from a one-unit increase in the quantity of labor employed.Increasing marginal returnsWhen the marginal product of an additional worker exceeds the marginal product of the previous worker.Decreasing marginal returnsWhen the marginal product of an additional worker is less than the marginal product of the previous worker.Derived demandThe demand for a factor of production, which is derived from the demand for the goods and services that it is used to produce.注意同学们经常错的知识点1、 机会成本一定是备选项中最好的那个。在研究market时，包含explicit cost 和implicit cost。2、 对比优势时，看清求绝对优势还是比较优势！比较优势给的是哪一种情况。3、 一定要搞清S和D的影响因素！给什么分析什么。作为产品，互为替代品或互补品，影响D；但作为生产要素（in production）互为替代品或互补品，影响S。4、 完全竞争市场中，P vs AVC, shut down point，supply curve （short run）；P vs ATC, economic profit or loss (short run or long run)5、 MC=MR, profit maximizing； MR=0，total revenue maximized； P=MC，market efficient； P=ATC, normal profiteconomic profit=06、 在有外部性存在的情况下求deadweight loss！不能错！ 7、 Tax & subsidylump sum subsidy or tax：无论在何种市场里对MC都无影响，MC和MR都不变，所以P和Q不会变，但是影响ATC，所以会影响economic profit or loss。（2008.1）Per unit subsidy or tax: （2006.2；2007.1）影响MC, 从而影响Q。收税/补贴多少。价格差多少，就收/补多少。8、 不要主观行事，客观对待题目，给什么答什么，不能想当然！