1、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：O
2、pportunity 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
3、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
4、 and trade can increase productivity and output. Economic growth could be achieved by:Increase in the quantity of resourcesIncrease in the quality of existing resourcesTechnological advancementsd. Trade can be good to both countries even if one country has the absolute advantage in all products. Two
5、 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
6、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
7、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Taste Tax /SubsidyCost of inputIncome TechnologyPrice of substitute good Price of
8、complement goodTaxExpectation of pricecost of inputstechnology and productivitySubsidy/taxExpectation of price Price 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 shortagepr
9、ice 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
10、 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 inela
11、stic 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=(%cha
12、nge 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 elast
13、ic）6. Tax incidence and deadweight loss 税收负担和无谓损失1.monopoly Perfectly 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
14、, 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.Crea
15、te 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
16、 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
17、: 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
18、，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
19、 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 M
20、C 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
21、，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 abl
22、e 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
23、 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，
24、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 productMRP Lhiring of labor at the current wage2. Marginal revenue product 边际产量值增加一单
25、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. pr
26、ices 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 Governmen
27、t 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excludable non
28、excludableRival Private goods Common resourcesnonrival Natural monopoly goods Public 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
29、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
30、 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
31、 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
32、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
33、，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！
