填空题[A]Thetake-upofEVs—whichrunentirelyonelectricitystoredinrechargeablebatteries—isseenascentraltotheplantocutthetransportsector'scarbonemissions,bothhereandacrosstheEuropeanUnion.Itispredictedthatwewillberunningatotalof800,000EVsinBritainby2020,andasaresulttheracetoinstallarecharginginfrastructureiswellunderway.TransportforLondon(TfL)recentlyannounceditwillhave1,300EVchargingpointsinLondonby2013—morethanthecurrentnumberofpetrolstationsinthecapital.TheLondonmayor,BorisJohnson,isontherecordassayinghewantstomakethecitytheelectriccarcapitalofEurope.[B]However,thepowercompanies,sensingagoodbusinessopportunity,arenowvyingtosignupelectriccar-owninghouseholdswiththeofferofcheaperandfasteroff-peakhomechargingthatwillcutthetimeittakestorechargethevehicle—freeingittomakemorejourneys,andmakingthemmoreattractivetobuyers.Sofar,EDF,BritishGas,andmostrecentlynpowerhavesaidtheywillbetargetingEVuserswithspecialhomeservicesaswellascheapertariffsforrechargingvehicles.[C]Whatwouldmakeyouconsiderbuyinganelectriccar?Theyofferagreenwaytogetaround,withthechancetobypasspetrolstations.AndtheyareexemptfromroadtaxandLondon'scongestioncharge.Energycompanynpower(英国电力公司)thisweekrevealedthat33%ofUKdriverswouldthinkaboutbuyinganelectricvehicle(EV)inthenextfiveyears,risingto41%whenthebenefitswereexplained.[D]ButdespitetheintroductioninJanuaryofagenerous￡5,000governmentpurchasegranttoencouragemorepeopletotaketheplunge,it'sfairtosaythatsalesofelectricallypoweredcarsintheUKareyettoreallytakeoff.Justover500peopletookthegovernmentuponitsofferinthefirstquarterofthisyear.Theirhighprices—typicallyabout￡25,000afterthegrant—plusalackofmodelsbymajorcarmakersandashortageofchargingpoints,haveheldbacksales.However,thelasttwopointsareabouttochange.[E]SpeakinginBerlinlastweek,npower'sheadofe-mobility,PhilEvans,toldGuardianMoneythatthecompanyseesEVsasamajoropportunity,andasaresultitisworkingonbuildingan"upgradable"charginginfrastructurethatwilldevelopasthecars'powersystemsbecomemoresophisticated.[F]PotentialbuyersnowhaveachoiceofsevenmodelsintheUK,with13moreontheway,whileEDFEnergy(英国电网),BritishGasandnpowerhaverecentlyannouncedplanstostartofferingtoinstallfasterandcheaperchargingpointsincustomers'homes,inamovetheyhopewillhelpkick-startsales.Thecompaniesarebankingonthefactthatbuyersofthelatest,moreconsumer-friendlyelectriccars,suchastheNissanLeaf,aregoingtoboostdemandforelectricity.[G]PlansarealsounderwaytoincreasethenumberofchargingpointsatavarietyoflocationsacrosstheUK—andsoonitwillbepossibleforhomeownerstoupgradetheirgaragestoallowfaster,saferhomecharging.Untilrecently,mostownersofplug-in-to-rechargeelectriccarshavehadtorelyonthetraditionalthree-pointhouseholdplug,andwaitabouteighthourstofullyrechargetheirvehicleathome.

填空题设随机变量X的密度函数为，若，则a=________．

填空题已知r(α 1 ，α 2 ，…，α s )=r(α 1 ，α 2 ，…，α s ，β)=m，r(α 1 ，α 2 ，…，α s ，γ)=m+1，则r(α 1 ，α 2 ，…，α s ，β，γ)=_____。

填空题设B≠O为三阶矩阵，且BA=O，则r(B)=________．

填空题函数z=2xy-3x 2 -2y 2 +20的极______值是______．

填空题∫sec 2 5xdx=__________．

填空题求心脏线ρ=4(1+cosθ)和直线θ=0及围成的图形绕极轴旋转所成旋转体体积为________．

填空题已知∫f(x)dx=F(x)+C，则∫f(sinx)cosxdx=______。

填空题积分=______．

填空题=_______

填空题设A～B，其中，则x=________，y=________．

填空题设a＞0，a≠1，且则p=________

填空题定积分=________。

填空题若总体X～N(0，32)，X1，X2，…，X9为来自总体样本容量为9的简单随机样本，则Y=服从________分布，其自由度为________．

填空题微分方程yy"一2(y") 2 =0的通解为___________．

填空题曲面x2+2y2+3z2=21在点(1，-2，2)处的法线方程为______．

填空题设A～B，其中，则x=________，y=________．

填空题已知ξ1=(-9，1，2，11)T，ξ2=(1，-5，13，0)T，ξ3=(-7，-9，24，11)T是方程组的解，则方程组的通解是______．

填空题设函数y=y(x)由确定’则y=y(x)在x=ln2处的法线方程为________．