2025年AP微观经济知识点

SherryYao530299APMICROREVIEWBasicEconomicConcepts(8%14%)Scarcity,choice,andopportunitycostScarcity:thelimitednatureofsociety’sresourcesEconomics:thestudyofhowsocietymanagesitsscarceresourcesPeoplefacetradeoff(efficiencyorequality)Opportunitycost:whatevermustbegivenuptoobtainsomeitemProductionpossibilitiescurveTheproductionpossibilitiescurveshowsthebinationsofoutputthattheeconomycanpossiblyproducegiventheavailablefactorsofproductionandtheavailableproductiontechnologyQy1、TheoppcostofQxequalstheslopeofcurve2、TheoppcostofQxishigher,thecurveissteeper3、oppcostisconstant,thePPFisstrictline4、Technologyadvance→PPFshiftIInefficientQxparativeadvantage,absoluteadvantage,specializationandtradeparativeadvantage:theabilitytoproduceagoodataloweropportunitycostthananotherproducerAbsoluteadvantage:theabilitytoproduceagoodusingfewerinputsthananotherproducersTradecanbenefiteveryoneinsocietybecauseitallowspeopletospecializeinactivitiesinwhichtheyhaveaparativeadvantage、EconomicsystemPropertyrightsandtheroleofincentivesPropertyrights:theabilityofanindividualtoownanexercisecontroloverscarceresourcesMarketpowerMarketfailure:allocateresourcesinefficiently←NegativeexternalityIncentive:somethingthatinducesapersontoact(theprospectofapunishmentorareward)MarginalanalysisMarginalchange:asmallincrementaladjustmenttoaplanofactionPeoplemakechoicewhenmarginalbenefit＞marginalcost2、TheNatureandFunctionsofProductMarkets(55%70%)SupplyandDemand(15%20%)MarketequilibriumAsituationinwhichthemarketpricehasreachedthelevelatwhichquantitysuppliedequalsquantitydemandedDeterminantsofsupplyIne:ine↓,demandofnormalgoods↓,demandofinferiorgood↑Pricesofrelatedgoods:priceofsubstitute↓,demandofanothergood↓priceofplements↓,demandofanothergood↑TastesExpectations:expecthigherine,demand↑Numberofbuyers:buyers↑,demand↑DeterminantsofdemandInputprice:inputprice↑,supply↓Technology:advanceintechnology,supply↑Expectations:expectthepriceofgoods↑,supply↑Numberofsellers:numberofsellers↑,supply↑PriceandquantitycontrolsDemand→,price↑,quantity↑Supply→,price↓,quantity↑ElasticityDemandCurveInelastic:Price↑,totalrevenue↑DemandCurveElastic:Price↑,totalrevenue↓NormalGoods&IneElasticity:TheQuantityofNormalGoodsmovesthesamedirectionwiththePercentageofIne对normalgoods得需求量与收入变动同方向运动TheElasticityofNormalGoodsisusuallypositiveInferiorGoods&IneElasticityTheQuantityofInferiorGoodsmovestheoppositedirectionwiththePercentageofIne对inferiorgoods得需求量与授予变动反方向运动TheElasticityofInferiorGoodsisusuallynegativeExy＞1,substitute,Exy＜1,plementaryConsumersurplus,producersurplus,andallocativeefficiencyConsumersurplus:theamountabuyeriswillingtopayforagoodminustheamountthebuyeractuallypaysforitProducersurplus:theamountasellerispaidforagoodminustheseller’scostofprovidingitAllocativeefficiency:thelastunitprovidesmarginalbenefittoconsumer=themarginalcosttoproducerTaxincidenceanddeadweightlossTaxincident:themannerinwhichtheburdenofataxisasharedamongparticipantsinamarketElasticity↑,thetaxburden↓Deadweightloss:thefallintotalsurplusthatresultsfromamarketdistortionsuchastaxTheoryofconsumerchoice(5%10%)TotalutilityandmarginalutilityTotalutility:TheaggregatelevelofsatisfactionorfulfillmentthataconsumerreceivesthroughtheconsumptionofaspecificgoodorserviceMarginalutility:gainfromanincrease,orlossfromadecrease,inthe

consumption

ofthatgoodorserviceUtilitymaximization:equalizingmarginalutilityperdollar、(MUX/PX=MUY/PY)IneandsubstitutioneffectsProductionandCosts(10%15%)ProductionfunctionsProductionfunction:therelationshipbetweenthequantityofinputsusedtomakeagoodandthequantityofoutputofthatgoodThequantityoftheinput↑,theproductionfunctiongetsflatterMarginalproductanddiminishingreturnsMarginalproduct:theincreaseintheamountofoutputfromanadditionalunitoflaborDiminishingreturn:thepropertywherebythemarginalproductofaninputdeclinesasthequantityoftheinputincreasesShortruncostsFixedcostintheshortrunLongruncostsandeconomiesofscaleVariablecostinthelongrunEconomiesofscale:thepropertywherebylongrunaveragetotalcost↓asthequantityofoutput↑Diseconomiesofscale:thepropertywherebylongrunaveragetotalcost↑asthequantityofoutput↑Constantreturnstoscale:thepropertywherebylongrunaveragetotalcoststaysthesameasthequantityofoutputchangesCostminimizinginputbinationandproductiveefficiencyEfficientscale:thequantityofoutputthatminimizedaveragetotalcostProducesgoodsinthequantitywhereMCintersectwithATC(minATC)Firmbehaviorandmarketstructure(25%35%)ProfitShortrunprofit:WhenATC＜(MR=MC)Longrunprofit(Normalprofit)=zeroEconomicprofit:totalrevenuetotalcost(explicit+implicit)Accountingprofit:totalrevenuetotalexplicitcostProfitMaximization:producewhereMC=MRPerfectpetitionCharacteristics:PricetakesFreeentry&exitManysellers&buyersFullysubstitutablePerfectlyelastic(demandcurveHomogenousLongrun:P=ATCMC=MR=PProfitmaximization:MC=MR=P=ATCShortrunsupplyandshutdowndecision:1、P<ATC:EconomicLoss2、AVC<P<ATC:OperateintheShortrunbutexitinthelongrun3、P=AVC/P<AVC:shutdowninshortrunShortrunsupply=MCShortrunsupply=MCMarketMarketFirmFirmMonopolyCharacteristics:singlesellerHighbarrierstoentryNosubstitutes(havekeyresources)InelasticPricemakerEconomicsprofit(P＞MC=MR)P*P*Profitmaximization:producequantityinQ*,priceinP*Naturalmonopoly:asinglefirmcanproduceoutputatalowercostthancanalargernumberofproducers(MChorizontal)Inefficiencyofmonopoly:Price＞MR=MC→deadweightlossPricediscrimination:thebusinesspracticeofsellingthesamegoodatdifferentpricestodifferentcustomers(reduceconsumersurplus→profit)Socialoptimal:MC=DMonopolypetitionCharacteristics:monopoly＜numberofsellers＜petitivemarketImperfectsubstitutesImperfectinelasticityHeterogeneousproductsPricemakerLongrunprofit=zeroMR=MCMR=MCDecideP*andQ*ShortrunmonopolypetitionP*=ATCEcoProfits=0P*=ATCEcoProfits=0P*>minATCP*>MCP*>MRLongrunmonopolypetitionExcesscapacity:thequantityproduced＜efficientscale→excesscapacitytheprice＞marginalcost→markupTheproductvarietyexternality:positiveexternalityThebusinessstealingexternality:negativeexternalityOligopolyCharacteristics:fewsellerscontrolthewholemarketFewersubstitutesPricemakerInterdependenceinpricingInefficiencyEconomicprofitP＞MC、P＞MRCollusion:anagreementamongfirmsinamarketaboutquantitiestoproduceorpricestochargeCartel:agroupoffirmsactinginunisonGametheory:thestudyofhowpeoplebehaveinstrategicsituationNashequilibrium:reachedwhenthechoicesofallfirmsaresuchthatthereisnootherchoicethatmakesanyfirmbetteroff(increasesprofitsordecreaseloss)Dominantstrategy:astrategythatisbestforaplayerinagameregardlessofthestrategieschosenbyotherplayersTheoutputeffect:P＞MC,output↑,profit↑Thepriceeffect:Q↑,P↓,profit↓Outputeffect＞priceeffect→increaseproduction3、FactorMarkets(10%18%)DerivedfactordemandDemandforafactorofproductionMarginalrevenueproductTheadditionunitofproductbringsadditionrevenueHiringdecisionsinthemarketsforlaborandcapitalApetitive,profitmaximizingfirmhiresworkersuptothepointwheretheVMPL=wageMarketdistributionofineWage=VMPL=PricexMPLLabordemandshiftP↑,VMPL↑,labordemand→AdvanceintechnologyThesupplyofotherfactorsLaborsupplyshiftChangesintastesChangesinalternativeopportunitiesimmigration4、MarketFailureandtheRoleofGovernment(12%18%)ExternalitiesPositiveexternality:socialbenefit＞privatebenefitNegativeexternality:socialcost＞privatecostCorrectivetax:ataxdesignedtoinduceprivatedecisionmakerstotakeaccountofthesocialcoststhatarisefromanegativeexternalitySubsidiesPublicgoodsPrivategoods:excludable&rivalinconsumption(clothing/congestedtollroads)Publicgoods:notexcludable¬rivalinconsumption(nationaldefense/uncongestednontollroads)monresources:notexcludable&rivalin