AP微觀經(jīng)濟(jì)梳理

濟(jì)寧孔子國際學(xué)校AP 微觀經(jīng)濟(jì)學(xué)知識點(diǎn)梳理 I. Basic Economic Concepts 經(jīng)濟(jì)學(xué)基礎(chǔ)概念 (814%) 選擇A.Scarcity, choice and opportunity cost 稀缺性（概念），選擇（概念），機(jī)會成本（計算）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 生產(chǎn)可能性邊界曲線（識圖，計算）橫縱坐標(biāo)軸分別是兩種產(chǎn)品的產(chǎn)量，斜率是機(jī)會成本。a. 曲線彎: law of increasing opportunity cost（生產(chǎn)鞋和電腦的資源不可相互替代）；because the resources are not perfectly adaptable.b. 直的: 生產(chǎn)兩種物品的資源可完全替代，也就是說資源完全可以通用，機(jī)會成本恒定。C.Comparative advantage, absolute advantage, specialization and trade 比較優(yōu)勢（計算），絕對優(yōu)勢（計算），專業(yè)化（概念），貿(mào)易（概念）a. 絕對優(yōu)勢：more productive. 生產(chǎn)一單位less time or less input。（或者單位time或input生產(chǎn)更多）如果給的是時間，則不用換算b. 比較優(yōu)勢：lower opportunity cost. xxx/hour 別忘了是與本國生產(chǎn)另一產(chǎn)品的opportunity cost 相比較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計劃經(jīng)濟(jì)和市場經(jīng)濟(jì)（概念），產(chǎn)權(quán)（概念），激勵的作用（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,供求決定價格，市場決定生產(chǎn)多少消費(fèi)多少。如果是mixed economy，則market和government共同決定。F. Marginal analysis 邊際思維（概念）MB>MC, 做這件事。Marginal=additionalII. The Nature and Functions of Product Markets 產(chǎn)品市場的特點(diǎn)和功能 (5570%) A. Supply and demand 供給和需求 (1520%)1. Market equilibrium 市場均衡 （先Q后P）Equilibrium quantity 由 Qs 和Qd決定：Qs=QdD 的變動才會引起P的變動2. Determinants of supply and demand 供給和需求的影響因素影響需求 影響供給TasteTax /SubsidyCost of inputIncomeTechnologyPrice of substitute good Price of complement goodTaxExpectation of pricecost of inputstechnology and productivitySubsidy/taxExpectation of pricePrice of other goods切記：Price變動導(dǎo)致沿著曲線的移動，而不是曲線本身的移動；上表里的因素都是導(dǎo)致曲線本身移動的。S,D同向移動：左（Q減少，P不定）；右（Q增加，P不定）S,D反向移動：內(nèi)（P增加，Q不定）；外（P減少，Q不定）3. Price control Price ceiling: Creates shortageprice floor：最低工資是經(jīng)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彈性a. Price elasticity of demandEd=(%change in quantity demanded of good x)/(%change in the price of good X)b. Price elasticity of supply一定要分清問的是關(guān)于supply還是demand需求和供給價格彈性算絕對值，不關(guān)心正負(fù)號；彈性為無窮時，叫Perfectly Elastic完全彈性，彈性大于1時，叫Relatively Elastic，彈性等于1時，叫Unit elastic，彈性小于1時，叫relatively inelastic，彈性等于0時，perfectly inelastic完全剛性。應(yīng)用：彈性為elastic時，P降低，Total Revenue會增加，因為Q增加的程度大于P降低的程度；為inelastic時，P降低，Total Revenue會減少，因為Q增加的程度小于P降低的程度。影響價格彈性的因素：奢侈品的彈性大于1，必需品的彈性小于1；時間長彈性大于1；替代品多彈性大于1；占收入比重大彈性大于1。c. Income elasticity of demandEI=(%change in quantity demanded of good X)/(%change in income) 需求收入彈性正號表示物品是normal goods，負(fù)號表示inferior goodsd. Cross-price elasticity of demandEx,y=(%change in quantity demand of good X)/(%change in price good Y)交叉需求彈性正號表示A和B為substitution，負(fù)號表示A和B為complementary。5. Consumer surplus, producer surplus and market efficiency剩余和市場效率消費(fèi)者剩余=支付意愿市場價格；生產(chǎn)者剩余=市場價格生產(chǎn)成本Market efficiency： MB=MC, Total Surplus最大Supply do the same（longer time, more elastic）6. Tax incidence and deadweight loss稅收負(fù)擔(dān)和無謂損失1.monopolyPerfectly competitive marketPer-unit subsidy/taxMC&ATC both changeOnly ATC changeLump-sum subsidy/taxNothing changeNothing change2.Tax 永遠(yuǎn)是向sellers 收的，只是sellers根據(jù)elasticity of demand and supply 的不同來向consumer收錢。3.Tax or subsidy/negative, positive externality會造成deadweight loss, but shift of supply or demand curve 不會，因為它們形成了新的均衡點(diǎn)。4.收稅之后，suppliers & demanders charge different money.(one below, one above)5.在畫deadweight loss的時候，尖點(diǎn)永遠(yuǎn)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 消費(fèi)者選擇理論 (510%) 可能大題1. Total utility and marginal utility 總效用和邊際效用Utility is the satisfaction or happinesslaw of diminishing marginal utility 2. Utility maximization: equalizing marginal utility per dollar邊際效用之比等于價格之比MU1/MU2 =P1/P2，在預(yù)算允許的條件下。3. Income and substitution effects收入效應(yīng)，替代效應(yīng)Income effect：normal: 都多買或少買substitution effect：normal: 一個多買一個少買inferior: income decrease 多買，price increase 少買 D. Production and costs生產(chǎn)與成本 (1015%)1. Production functions: short and long run短期和長期的生產(chǎn)函數(shù)Short run: only labor variableLong run: all variable2. Marginal product and diminishing returns邊際產(chǎn)量和邊際產(chǎn)量遞減規(guī)律MP of A= additional output/ additional input of AMarginal returns start diminishing when MP decreases as L increasesFC不變隨著labor的增加，MC增加（因為生產(chǎn)力下降）MC和MP的圖！3.Short-run costs短期成本曲線MC曲線最后是上揚(yáng)的，是因為，生產(chǎn)能力全部被利用之后，再增加邊際投入，就會出現(xiàn)邊際產(chǎn)量遞減，邊際成本遞增。4. Long-run costs and economies of scale長期成本曲線和規(guī)模經(jīng)濟(jì)長期有economies of scale規(guī)模經(jīng)濟(jì)，指隨著產(chǎn)量增加ATC不斷下降，反之則是diseconomies of scale規(guī)模不經(jīng)濟(jì), constant returns to scale規(guī)模收益不變指產(chǎn)量變動而ATC不變，或者說投入增加的倍數(shù)與產(chǎn)出增加的倍數(shù)相同。規(guī)模經(jīng)濟(jì)的產(chǎn)生是因為specialization& ability to purchase5. Cost minimizing input combination成本最小化的要素組合MPL/PL=MPK/PKE. Firm behavior and market structure企業(yè)行為和產(chǎn)業(yè)組織 (2535%) 必出大題1. Profit利潤a. Accounting profit，economic profit會計利潤（總收益-顯性成本）和經(jīng)濟(jì)利潤（總收益-顯性成本-隱性成本）b. Normal profit指的經(jīng)濟(jì)利潤為0（但依然賺著會計利潤）d. Profit maximization對各種類型的企業(yè)都適用的利潤最大化條件是當(dāng)MR=MC時的產(chǎn)量，即使沒有恰好相等的點(diǎn)，也要選擇MR剛剛大于MC的那個產(chǎn)量。2. Perfect competition完全競爭Price taker No economic profit in the long runa. Profit maximizationP=AR是恒等式，因為P=TR/Q,AR=TR/Q。完全競爭市場很特別，企業(yè)獲得利潤最大化的產(chǎn)量是在P=MC=MR=AR時。b. Short-run supply and shutdown decision短期的企業(yè)供給曲線是MC曲線在AVC上方的那段；在短期，如果P<AVC，企業(yè)選擇停業(yè)；市場長期供給曲線是水平的。c. Behavior of firms and markets in the short run and in the long runprofit enter; loss exit計算短期profit或loss時，應(yīng)找準(zhǔn)P和ATC，Profit=TR-TC=(P-ATC)*Qd. Efficiency and perfect competition因為P(MB)=MC，所以完全競爭市場有效率。=64 1jhjjjjn73. Monopoly壟斷特點(diǎn)：只有一家企業(yè)，因此需求曲線向右下方傾斜；自己定價，是price maker；有壁壘，因此有長期經(jīng)濟(jì)利潤。a. Sources of market powerOwnership; legal; natural(economies of scale)b. Profit maximization先通過MR=MC的條件確定產(chǎn)量Q，再通過需求曲線找到對應(yīng)的P，這是壟斷企業(yè)利潤最大化的條件。P=AR>MRc. Inefficiency of monopoly 壟斷無效率因為產(chǎn)量少于需求并且收取高于期望的價格，所以壟斷是效率低的。too little of the production and charges too high a price.會畫圖：知道Revenue maximizing（MR=0的產(chǎn)量），profit maximizing（MR=MC）, efficient maximizing（P=MC）與fair return企業(yè)經(jīng)濟(jì)利潤為0（ATC和D相交）這四種情況下的產(chǎn)量和價格。d. Price discrimination 價格歧視1.consumer surplus=02.produce at allocative efficient point3.be able to separate buyers and block them from retailing.4. Monopolistic competition壟斷競爭a.Product differentiation and role of advertising有許多賣者，每個賣者提供略有差別的產(chǎn)品，無壁壘，有決定價格的能力，做廣告的必要性b.Profit maximization與壟斷類似。先通過MR=MC的條件確定產(chǎn)量Q，再通過需求曲線找到對應(yīng)的P，這是壟斷競爭企業(yè)利潤最大化的條件。P=AR>MR。c.Short-run and long-run equilibrium短期有profit或loss，吸引新企業(yè)進(jìn)入或舊企業(yè)退出市場。進(jìn)而達(dá)到長期均衡，D與ATC曲線相切，切點(diǎn)剛好是MC=MR投影到D的點(diǎn)，長期利潤為0。因為在ATC的下降部分相切，所以有規(guī)模經(jīng)濟(jì)。d.Excess capacity and inefficiency壟斷競爭無效率體現(xiàn)在：產(chǎn)能過剩 Excess capacity，價格過高 P>MC5. Oligopoly 寡頭a.Interdependence, collusion and cartels卡特爾、聯(lián)盟、互賴受反托拉斯法的約束，有market power，企業(yè)數(shù)量很少；合作的話，如同壟斷一般獲利最大，如果不合作，則利潤不高。b.Game theory and strategic behavior會利用支付矩陣分析占優(yōu)策略。必考。題目中可能一方有占優(yōu)策略另一方無占優(yōu)策略，那么沒有的那方要先揣測出有占優(yōu)的那方的意圖。F. Factor Markets要素市場. (1018%) 出大題1. Derived factor demand派生需求對一種生產(chǎn)要素的需求來自（派生自）對另一種產(chǎn)品的需求。D for productprice of productMRPLhiring of labor at the current wage2. Marginal revenue product邊際產(chǎn)量值增加一單位勞力所引起的產(chǎn)值的變化 MRP=MP*MR=MP*P (perfectly competitive market)3. Labor market and firms hiring of labor (perfectly competitive market)D=MRP曲線，MRP=P*MPL S=wage利潤最大化雇用人數(shù)：w=VMP=MRP=P*MP竅門：a. 影響需求1. product demand2. productivityTechnical progressQuantity of other resourcesquality of variable resources3. prices of other resourcesSubstitute resourcesSubstitution effectIncome effectComplementary resourcesb. 影響供給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市場失靈和政府管制 (1218%)1. Externalities外部性，出大題a.Marginal social benefit and marginal social costb.Positive externalities正外部性：MSB>MSC under allocation subsidy(per unit) lump sum subsidy has no effect on the graph.c.Negative externalities負(fù)外部性：MSB<MSC over allocation tax2. Public goods公共物品excludablenonexcludableRivalPrivate goodsCommon resourcesnonrivalNatural monopoly goodsPublic goods3. Public policy to promote competitiona.Antitrust policycompetitionb.Regulation政府對壟斷的管制如果政府給壟斷、壟斷競爭、完全競爭企業(yè)一次性補(bǔ)貼或一次性征稅（lump sum subsidy or tax），不會對企業(yè)的MC產(chǎn)生影響，因此不會影響利潤最大化產(chǎn)量和價格。但由于影響了ATC，導(dǎo)致利潤或loss有變化。如果征稅或補(bǔ)貼是按單位per unit，則會影響MC，繼而影響利潤最大化產(chǎn)量和價格。4. Income distribution促進(jìn)市場競爭的政策a.Equity認(rèn)識洛倫茲曲線：是反映收入不平等程度的?；嵯禂?shù)是不規(guī)則圖形面積比上大三角面積，越小越接近公平。b.Sources of income inequality收入不平等的來源：歧視，教育程度不同，能力不同，動機(jī)不同。必背定義 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.注意同學(xué)們經(jīng)常錯的知識點(diǎn)1、 機(jī)會成本一定是備選項中最好的那個。在研究market時，包含explicit cost 和implicit cost。2、 對比優(yōu)勢時，看清求絕對優(yōu)勢還是比較優(yōu)勢！比較優(yōu)勢給的是哪一種情況。3、 一定要搞清S和D的影響因素！給什么分析什么。作為產(chǎn)品，互為替代品或互補(bǔ)品，影響D；但作為生產(chǎn)要素（in production）互為替代品或互補(bǔ)品，影響S。4、 完全競爭市場中，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況下求deadweight loss！不能錯！ 7、 Tax & subsidylump sum subsidy or tax：無論在何種市場里對MC都無影響，MC和MR都不變，所以P和Q不會變，但是影響ATC，所以會影響economic profit or loss。（2008.1）Per unit subsidy or tax: （2006.2；2007.1）影響MC, 從而影響Q。收稅/補(bǔ)貼多少。價格差多少，就收/補(bǔ)多少。8、 不要主觀行事，客觀對待題目，給什么答什么，不能想當(dāng)然！