中级微观经济学试题I

1INTERMEDIATEMICROECONOMICSExerciseI1.ThedemandcurveofmovieisQ=500−5P.Ifthecurrentpriceofticketsis35,thepriceelasticityofdemandatthecurrentpriceisa.-0.2b.-0.54c.-0.68d.-12.Whichofthefollowingutilityfunctionswouldnotbeconsistentwiththenotionthatxandyareboth“goods”withpositivemarginalutilities?a.(,)2Uxy=yx.b.U(x,y)=x+y.c.(,)Uxy=xy.d.U(x,y)=x/y.3.Iftwogoodsareperfectcomplements:a.thereisablisspointandtheindifferencecurvessurroundthispoint.b.consumerswillonlybuythecheaperofthetwogoods.c.indifferencecurveshaveapositiveslope.d.noneoftheabove.4.Accordingtothegraphshown,ifthegovernmentimposesapriceceilinginthismarketatapriceof$5.00,theresultwouldbea.ashortageof20units.b.ashortageof30units.c.asurplusof20units.d.asurplusof40units.25.Ifutilityisgivenby22(,)2Uxyxyyx,thisperson’sindifferencecurvesarea.parabolas.（抛物线）b.hyperbolas.（双曲线）c.concentriccircles.（同心圆）d.straightlines.6.Whichofthefollowingisanexampleofanormative,asopposedtopositive,statement?a.Thepriceofgasolinecamedownsharplyduringthesecondhalfof2006.b.Ifthegovernmentweretosetamaximumlegalpriceongasoline,thentherewouldbeashortageofgasoline.c.Incometaxesshouldbereduced.d.Thefederalgovernmentobtainsmuchofitsrevenuefromincometaxes.7.Ifanindividual’sutilityfunctionforcoffee(x)andcream(y)isgivenbyU(x,y)=min(x,5y),thedemandfunctionforcoffeeisgivenbya.X=I/2px.b.X=I/(px+py).c.X=I/(px+0.2py).d.X=I/(px+py)2.I.TrueorFalse.Pleasewriteyouranswerinthetable.123451.Engelcurvesalwaysslopeupwards.2.Iftherearetwogoods,ifaconsumerprefersmoreofeachgoodtoless,andifshehasdiminishingmarginalrateofsubstitution,thenherpreferencesareconvex.3.IfsomeonehasautilityfunctionU=2min{x,y},thenxandyareperfectsubstitutesforthatperson.4.Anincreaseinanindividual’sincomewithoutchangingrelativepriceswillshifttheindifferencecurvesoutward.5.Tangenciesofindifferencecurvestothebudgetconstraintmustbepointsofutilitymaximization.II.CalculationandGraph1.Drawgraphswithquantitiesofpizzaonthehorizontalaxisandcocaontheverticalaxistoillustratethefollowingsituations.Ineachcasedrawtwodifferentindifferencecurvesandmakealittlearrowpointinginthedirectionofgreaterpreference.a.Marvinlovespizzaandhatescoca.b.Marvinhatescocaandiscompletelyindifferenceaboutpizza.32.PatrickhasautilityfunctionU(x1,x2)=48x11/2+x2,wherex1ishisconsumptionofnutsandx2ishisconsumptionofberries.Hisincomeis217,thepriceofnutsis3andthepriceofberriesis1.HowmanyunitsofberrieswillPatrickdemand?Ifhisincomedoublesandpricesstayunchanged,willhisdemandforbothgoodsdouble?3.JustinhastheutilityfunctionU=xy.Thepriceofxis2,thepriceofyispy,andhisincomeis40.Whenhemaximizesutilitysubjecttohisbudgetconstraint,hepurchases5unitsofy.Whatmustbethepriceofyandtheamountofxconsumed?