设a=(a1,a2,…,an)T,a1≠0,其长度为║a║,又A=aaT,(1)证明A2=║a║2A;(2)证明a是A的一个特征向量,而0是A的n-1重特征值;(3)A能相似于对角阵Λ吗?若能,写出对角阵Λ.
暂无解析
Passage1
Questions1to5arebasedonthefollowingpassage:
DoyouwanttosaywhatyouthinkinalettertothePresidentoftheUnitedStates?You’llgetareplyfromhim—writteninink,nottyped—afteronlyafewdays.
ThePresidentgetsabout4,000letterseveryweek.HeanswerseveryonewhowritestohimonspecialWhitesHousepaper.Buthedoesn’tneedalotoftimeforit.Infact,heonlygives20minutesaweektolookathispersonalcorrespondence.Hehasthemostmodernsecretaryintheworldtohelphim.
It’scomputer,worth£800,000,whichhasitsownroomsonthefirstflooroftheWhiteHouse.IthasabankofelectronicpenswhichwritelikethePresidentwrites,inhisfavoritelightblueink.EachletterthePresidentreceivesgetsanumber,accordingtothetypeofansweritneeds.Thepensthenwritethecorrectreplyforit,accordingtothenumber.Eachlettertakeslessthanasecondtowrite.AWhiteHouseofficialsaid,“It’snotimportantthatletterscomefromacomputer.EachlettersayswhatthePresidentwantstosay.”
1.forareplyfromthePresident.
A.YouhavetowaitalongtimeB.Youonlyhavetowaitseveraldays
C.YouhavetowaitatleastonemonthD.Youonlyhavetowaitafewweeks
2.ThereplyfromthePresident.
A.isalwaysprintedB.isalwaystyped
C.isalwayswrittenininkD.isalwayswrittenbyhimself
3.Ittakesthecomputertowritetenletters.
A.nomorethantensecondsB.alittlemorethantenseconds
C.lessthantensecondsD.atleastonesecond
4.Thecomputercanbedescribedas.
A.expensivebutefficientB.possessingabeautifulhandwriting
C.heavyandinefficientD.thePresident’smostreliablesecretary
5.Itcanbeinferredfromthepassagethat.
A.thePresidentneverreadsanyletterswrittentohimbyordinarypeople
B.thePresidenthiresaveryefficientsecretarytodealwithhiscorrespondence
C.thePresidentdoesnotreallycareaboutthelettershereceiveseveryweek
D.thePresidentisassuredthatthecomputerexpresshisviewsintheletters
一初产妇,宫缩15小时自娩一3000g女婴,现胎儿娩出已8分钟,胎盘尚未娩出,阴道无流血,此时的处理下列何项不当
PartIVTranslation
Asthesourceofaluminumisalmostinexhaustible,wecanexpectthatmoreandmoreuseswillbefoundforthisversatilemetal.(PassageTwo)