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i是虚数单位,=( )
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高二下学期数学《》真题及答案
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设复数z=1+2ii是虚数单位则|z|=________.
.i是虚数单位若复数1-2ia+i是纯虚数则实数a的值为________.
i是虚数单位.复数3+i1-2i=.
若复数a-2+ii是虚数单位是纯虚数则实数a=.
若复数1+2i1+ai是纯虚数i为虚数单位则实数a的值是.
已知i为虚数单位a∈R若a-1a+1+i=a2-1+a-1i是纯虚数则a的值为
-1或1
1
3
-1
设m∈Rm2+m-2+m2-1i是纯虚数其中i是虚数单位则m=.
设复数z满足z•i=2﹣ii为虚数单位则z=________
i是虚数单位复数3+i1-2i=__________.
i是虚数单位i2015等于
1
﹣1
i
﹣i
若复数z=x+i1+i是纯虚数其中x为实数i为虚数单位则z的共轭复数=.
i是虚数单位1+i3等于
i
-i
1+i
1-i
若复数a2-l+a-1ii为虚数单位是纯虚数则实数a=
±1
-1
0
1
若复数z=i是虚数单位是纯虚数则实数m的值是________.
.已知i是虚数单位则复数=
-2+i
i
2-i
-i
若复数z=1-im+2ii为虚数单位是纯虚数则实数m的值为.
设m∈Rm2+m-2+m2-1i是纯虚数其中i是虚数单位则m=________.
若ibi+1是纯虚数i是虚数单位则实数b=______.
设复数z=1+2ii是虚数单位则|z|=__________.
i是虚数单位.复数3+i1-2i=.
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10分假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除把多余的词用斜线\划掉. 修改在错的词下划一横线并在该词下面写出修改后的词. 注意1.每处错误及其修改均仅限一词2.只允许修改10处多者从第11处起不计分. TheotherdayTomwasridingalongthestreetwhenacarranfastlytowardshim.Heturnedleftquicklyanditwastoolate.Thecarhithimselfandhefelloffhisbike.Thedriverofthecarwassofrighteningthatheranawayasfasthecould.SoonthedriverisoutofsightleavingTomhelplessonthespot.Fortunateawomanhappenedtoseeingitandrememberedthenumberofthecar.Shecalledapolicemanandtoldhimwhenhadhappened.Atthelastthedriverwascaughtandpunishedforhiswrongdoing.
30分When10girlsfromGardinerHighSchoolinMontanareceivedasumofmoneytodevelopaninventiontosolveareal﹣worldproblemtheydecidedtocreateasolar﹣poweredsheltertohelpthehomeless. Foroverayearthegirlshavebeenusingalltheirfreetimetocompletethe1. Theyhavethisamazinginternal内心的2thatI'veneverseeninanyindividualVioletMardiroateacheratGardinerHighwhois3withtheteamontheprojecttoldTheHuffingtonPost.Ithought4thatmaybesomeofthemwouldgiveupsay‘Ididn't5thismuchwork'buttheyhaven't.They'rejustworkinghardandthey'renotgivingupandthey'resuper6. Livinginalow﹣incomecommunitythegirlshaveseenthe7ofhomelessnessfirst﹣hand.Manyofthemarefromimmigrantfamiliesandhopedthe8whichispoweredbyrechargeablesolarpanels电子板wouldhelpthe9. Seventeen﹣year﹣oldMaggieMejiatoldtheHuffingtonPostthat10shehadnoprevious11experiencethegirlsfiguredoutasateamhowto12theshelterusinghow﹣tovideosandbooksthattaughtthemhowtocode.Butthemostimportant13learnedduringtheprojectisn'ttechnical. I'velearnedalotabout14othersworkingforthecommunityandbeingselflessandshowingabetterworldtootherpeopleand15someoneelse'slifeshesaid.TheprojectwascarriedoutwithDIYGirlsanonprofitthathelpsfundSTEM﹣sciencetechnologyengineeringandmath﹣projectsfor16. Mardirosiansaidalltheparticipatingstudentshave17theirinterestinSTEMthroughthisproject. Manyofthemdidn'tthinkaboutengineeringbefore.Theythoughtmaybethey'renot18outtobeanengineer.Butworkingtogethernowthey19theirskill﹣whetherawritingskilloradrawingskilloraspeakingskillthey'reall20inthisfield.Everyonehasfoundtheirimportanceinthispictureshesaid. 1A.course B.homework C.report D.project 2A.clock B.drive C.doubt D.pressure 3A.agreeing B.meeting C.working D.talking 4A.atthebeginning B.allthetime C.atthemoment D.onceagain 5A.receive B.expect C.believe D.mind 6A.excited B.confused C.surprised D.worried 7A.problem B.adventure C.choice D.difference 8A.equipment B.community C.machine D.shelter 9A.families B.homeless C.team D.research 10A.when B.until C.while D.because 11A.engineering B.managing C.teaching D.planning 12A.renew B.create C.protect D.describe 13A.skill B.fact C.lesson D.subject 14A.questioning B.following C.pleasing D.helping 15A.running B.leading C.changing D.experiencing 16A.children B.adults C.teachers D.girls 17A.imagined B.remembered C.discovered D.ignored 18A.left B.put C.picked D.made 19A.accept B.realize C.wonder D.share 20A.needed B.learned C.found D.discussed
已知函数fx=|x﹣1|﹣2|x+1|. Ⅰ解不等式fx≥x Ⅱ设fx的最大值为m若2ab+2bc+2ca=mabc∈R+求a+b+c的最小值.
已知函数gx=x2﹣2ax+1且函数y=gx+1是偶函数设fx=. 1求fx的解析式 2若不等式flnx﹣mlnx≥0在区间1e2]上恒成立求实数m的取值范围 3若方程f|2x﹣1|+k•﹣2=0有三个不同的实数根求实数k的取值范围.
在△ABC中角ABC的对边分别是abc且 Ⅰ求角A的大小 Ⅱ若a=2求△ABC面积的最大值.
函数y=+的值域为
设gx=ln2x+1则g4﹣g3+g﹣3﹣g﹣4=
8分Everwonderedwhyfreshfruitsandvegetablesarethefirstthingyouseeinstoresorwhythebreadandmilkaresofaraway?Supermarketsspendmillionsofdollarsresearchingconsumer消费者behaviourinordertodevelopwaystomakeyoubuymoreintheirstores. CHOICEmagazinetakesalookatsomeofthemorecommontrickstohelpyouavoidspendingmoremoneynexttimeyougoshopping. Experts专家sayturningtotherightwhenyouwalkintoashopisconnectedwithmostpeople'spreferenceforusingtheirrighthand. DrPaulHarrisonexpertatDeakinUniversitysaysastore'sentry入口isnottheonlyimportantpoint.ResearchintheUShasshownthatshopperswhotravelinananti﹣clockwise逆时针方向的directionwillspendabouttwodollarsmorepertripthanclockwiseshoppers. Researchmadeonshoppers'in﹣storemovementssuggestspeopletraveltosomeaisles过道only.Themostcommontriptotravelinstoresisaroundtheoutsidecirclewalkinginandoutoftheaislesasneeded.Asaresulttheendsofeachaislearewherethestoremakesthemostmoney. Whenyouenterabigsupermarketfreshfruitsandvegetablesareinthefirstshoppingarea.Althoughit'snotwisetofirstputfruitsandvegetablesintoyourshoppingbasketthisdepartmentissettomaketheshoppersfeelthatit'sfreshandhealthy.Peoplewhousethefreshfoodareasarealsolikelytospendmoremoneyinthestore. Bysettingupdifferentmarketplaceareasitfeelsasthoughwe'vevisitedseveraldifferentstoreswherewecangeteverythingweneedratherthanasinglebigshop.Eachoftheseareashasdifferentlightingandfloorcoverings.It'sallaboutcreatingamarket﹣likefeelsaysHarrison.Areasmakingandsellingbreadapartfromsmellinggoodgivetheimpressionthatthesupermarketcanbetrusted.It'slikethey'resaying‘Youcantrustusbecausewemakefood.' 1Whydopeopleturntotherightwhenenteringashop? A.Peoplearemostlyright﹣handed. B.It'seasierforthemtowalkinacircle. C.Freshfoodisoftenplacedontheright. D.Shoppingbasketsareusuallyontheright. 2WhatdoestheresearchintheUSfind? A.Mostshopperswalkanti﹣clockwise. B.Clockwisewalkersareoftenbigshoppers. C.Astore'sentryisthemostimportantpoint. D.Walkingdirectionsinfluenceconsumingbehaviour. 3Asforaisleswhatdosupermarketmanagersmostcareabout? A.Themiddle. B.Theends. C.Howlongtheyare. D.Howwidetheyare. 4Whatimpressiondoesasupermarkettrytogiveshoppersbymakingeachareadifferent? A.Itisfresh. B.Itoffersawidechoice. C.Itcoversabigarea. D.Itishealthy.
已知实数xy满足xcosα+ysinα=1则的最小值为.
设抛物线y2=6x的焦点为F准线为lP为抛物线上一点PA丄l垂足为A如果△APF为正三角形那么|PF|等于
函数fx=的图象可能是
已知函数fx=ax+lnx. Ⅰ若fx在区间01上单调递增求实数a的取值范围 Ⅱ设函数hx=﹣x2﹣fx有两个极值点x1x2且x1∈[1求证|hx1﹣hx2|<2﹣ln2.
25分假定你是李华你的英国朋友Tom对中国古诗Chinesepoetry很感兴趣.他来信请教有关知识.请给他回信内容包括 1.介绍中国古诗 2.你学习中国古诗经历和感悟 3.如何推广中国古诗? 注意1.词数100左右 2.可以适当增加细节以使行文连贯的 3.开头语已为你写好.
对两个变量y和x进行回归分析得到一组样本数据x1y1x2y2…xnyn则下列说法中正确的序号是. ①由样本数据得到的回归直线方程必过样本点的中心 ②残差平方和越小的模型拟合的效果越好 ③用相关指数R2来刻画回归效果R2越小说明拟合效果越好 ④若变量y和x之间的相关系数为r=﹣0.946则变量y和x之间线性相关性强
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已知函数fx=2sinxsinx++cos2x﹣sin2x 1求函数fx的单调递减区间 2若将函数fx图象上所有点的横坐标缩短为原来的倍纵坐标不变然后再向右平移φφ>0个单位长度所得函数的图象关于y轴对称.求φ的最小值
已知函数fx=sinx+cosxx∈R先将y=fx的图象上所有点的横坐标缩短到原来的倍纵坐标不变再将得到的图象上所有点向右平行移动θθ>0个单位长度得到的图象关于直线x=对称则θ的最小值为
九章算术是中国古代第一部数学专著是算经十书中最重要的一种成于公元一世纪左右它是一本综合性的历史著作是当时世界上最简练有效的应用数学.“更相减损术”便是九章算术中记录的一种求最大公约数的算法按其算理流程有如下流程框图若输入的ab分别为9636则输出的i为
某厂家生产甲乙丙三种不同类型的饮品・产量之比为234.为检验该厂家产品质量用分层抽样的方法抽取一个容量为72的样本则样本中乙类型饮品的数量为
15分Nightafternightshecametotuckmein给…盖好被子evenlongaftermychildhoodyears.1followherlongstandingcustomshe'dleandownandpushmylonghairoutofthewaythenkissmyforehead. Idon'tremember2itfirststartedannoyingme﹣herhandspushingmyhairthatway.FinallyonenightIshoutedoutatherDon'tdothatanymore﹣yourhandsaretoorough!Shedidn'tsay3inreply.Butneveragain4mymotherclosemyday5thatfamiliarexpressionofherlove. Timeaftertimewiththepassingyearsmy6thinkreturnedtothatnight.BythenImissedmymother'shandsmissedhergoodnightkissonmyforehead. NowthosehandsIoncethoughttobesoroughwerestilldoingthingsformeandmyfamily.Ifrequentlyrecalledthenightmyyoungvoicecomplained.OnenightcatchingMom'shandIspokeouthowsorryIwasforthatnight.Ithoughtshe'dremember7Idid.ButMomdidn'tknowwhatI8talkabout.Shehadforgotten﹣andforgiven﹣longago. ThatnightIfellasleepwithanew9appreciateformygentlemotherandhercaringhands.AndtheguiltthatIhadcarriedaroundforsolongwasnowhere10find.
在某一次数学测验中从全校抽出n名同学并记录其测验成绩满分100分进行统计•按照[50.60[6070[7080[8090[90100]的分组作出频率分布直方图并作出分数的茎叶图图中仅列出了分数在[5060[90100]的数据. 1求n和频率分布直方图中的xy的值 2在抽出的名学生中从分数在80分以上含80分的同学中随机选取2名求所抽取的2名同学至少有一名的成绩在[90100]内的概率.
6分Ifyou'reonthehuntforsomethingnewandinterestingtoreadyouhaveplentyofplacestogo.Thisweekwe'relookingatfourofthebestbookrecommendationsitesservicesorgroupsbasedonyournominations提名. GoodReads GoodReadsismorethanjustabookrecommendationsitealthoughitexcelsathelpingyoufindnewbookstoreadbasedontheonesyouenjoy.Youcanbuildavirtualshelfofbooksyouownorhavealreadyreadshareyourprogresswiththebooksyou'recurrentlyreadingratethebooksyou'vereadleavereviewsandconnectwithotherreaders. BookBub WhileBookBubisn'tstrictlyabookrecommendationserviceitdoesbringyousuper﹣low﹣costbooksbasedonyourinterestseveryday.TheserviceisfreeandwhenyousignupyoutellBookBubwhatkindsofbooksyouliketoread.Fromthereyou'llgetanemailfromBookBubeverydaywithbookdealsforthatday.Whenwesaydealwemeanit﹣manyofBookBub'stitlesarefreeentirely$0.99orjustacoupleofbucks. LibraryThing LibraryThinghasbeenaroundforalongtimeandisstillagreatuser﹣poweredbookratingsreviewandrecommendationsite.Theservicecallsitselftheworld'slargestbookclubandthat'salotliketheoverallfeel.Onceyousignupyou'llbeencouragedtostartaddingbooksyou'vereadandleavereviewsforthem.BehinditsbookratingsandreviewsthoughLibraryThingisapowerfultooltocatalogandorganizeyourentirebookcollection. Olmenta Ifyou'renotinterestedinregisteringforaccountsaddingyourownbooksoranyofthathassle麻烦Olmentacansuggestsomesolidtitlestoyoubasedongeneralpopularityandthecitationofthepeoplebehindthesite.It'sasimplelistofbookcoversthattheservicethinksyoushouldreadandafewgenresyoucanclickonifyou'relookingforsomethingspecificlikebusinessfictionchildren'stheatrepoetryornonfictionamongothers. 1Whichofthefollowingtwobookrecommendationsitesaskyoutorateandleavereviews? A.GoodreadsandBookBub B.BookBubandLibraryThing C.LibraryThingandOlmenta D.GoodreadsandLibraryThing 2Whichbookrecommendationsitecanhelpyougetsuper﹣low﹣costbooks? A.GoodReads B.BookBub C.LibraryThing D.Olmenta 3IfyouturntoOlmentayou. A.needtopaymore B.needtoaddyourownbook C.don'tneedtosignup D.don'tneedtolookforsomethingspecific
8分Father'sDayiscelebratedtodayin75countriesaroundtheworld.Inmypersonalworldit'sadayIliketothinkofmyfather'sfather. Ilearnedalotinmylaterlifefrommydad.ButIlearnedsomethingelseasakidnotevenyetinschoolfrommygrandfather.Ilearnedtobecurious.Littlethingsfathersandgrandfathersdocanchangethelifeofachildforever.InmycasethischangecamefromnecessityMymomneededsomeonetolookafterlittleAllenbarely4yearsoldduringtheschoolday.MygrandmothervolunteeredandmygrandfathercameupwithawayIcouldbewatchedwhileheworkedinhisclockmaker'sshop. HeseatedmeonachaireverydaywhileIwasthererightinfrontofhisbigworkbench.Hetoldmestories.Hehadagreatsenseofhumorandafunnywayofmakingabuh﹣buh﹣buhsoundwhenhesensedmyattentionwasweakeningandheencouragedmetoaskquestionsaboutanythinghewasdoing. NaturallyIwasusuallyaskingquestionsaboutclocks﹣﹣whatmadethehandsmovewhatthependulum钟摆didwhyyouhadtostopwindingjustbeforetheweighthitthestop.SometimesIjustaskedaboutwhichshinypartswentwhere. Mostofallheshowedmehowclocksworked.HetreatedmeasifIwereasortofsmallgrown﹣up.HenevertalkeddowntomenevertoldmeIwastooyoungtounderstand. AndsomygrandfathergrantedmetwothingsAloveofclocksandaneverlastingcuriosity. AsajournalistIturnedthatfascinationintoexplanationsofwhycomputersandsoftwaredowhattheydo﹣﹣andperhapsevenmoreimportantlywhytheyfailatthattask.Ihaven'tbeenafraidofopeninguptheinnardsandlookingforwhatiswrongwiththecomputer. 1Theauthorloveshisgrandfatherbecause. A.helearnedalotfromhim B.hetoldsomestoriestomakehimjoyful C.hewasbroughtupbyhisgrandfather D.hisfatherseldompaidattentiontohim 2Whilestayingwithhisgrandfathertheauthor. A.wastiredofthenoisesintheshop B.wasattractedbyhisgrandfather C.wasforcedtositstillonthechair D.wasalwaysaskingstrangequestions 3Whatistheauthor'sgrandfatherlikeinthepassage? A.Gentleandenthusiastic. B.Kindandexperienced. C.Activeanddependable. D.Patientandresponsible. 4Weknowaccordingtothepassagethattheauthor. A.doesn'tlivewithhisfatheranylonger B.becamemoreinterestedincomputersthanclocks C.wasinterestedinfindingoutaboutsomething D.oncebrokealotofclocks
8分Scientistsarepreparingtolaunchtheworld'sfirstmachinetocleanuptheplanet'slargestmassofoceanplastic.Theexpertsbelievethemachineshouldbeabletocollecthalfofthedetritusinthepatch﹣about40000metrictons﹣withinfiveyears.Inthepastfewweekstheyhavebeenbusyweldingtogethergianttubesthatwillsitonthesurfaceoftheseaandformtheskeletonofthemachinecreatingthelargestfloatingbarrierevermade. ThesystemoriginallydreamedupbyMr.SlatwillbeshippedoutthissummertotheGreatPacificGarbagePatchbetweenHawaiiandCaliforniaandwhichcontainsanestimated1.8trillionpiecesofplastic.Itwillbethefirsteverattempttotacklethepatchsinceitwasdiscoveredin1997. Mr.Slatwas16andstillatschoolwhenhewasdivinginGreeceandfirstsawforhimselftheamountofplasticpollutingthesea.Thereweremorebagsthanfishdownthereherecalls.TwoyearslaterhecameupwithasolutionquituniversityaftersixmonthsandsetupTheOceanCleanupasacompany.Mr.Slat23saysthefirstplastictoarriveonshorewillbeamajormilestone.WeasahumanitycreatedthisproblemsoIthinkit'sourresponsibilityalsotohelpsolveithesaid. TheGreatPacificGarbagePatchGPGPspans617763sqmiles﹣morethantwicethesizeofFranceandcontainsatleast79000tonsofplasticresearchfoundlastmonth.Mostofitismadeupofghostgear﹣partsofabandonedandlostfishinggearsuchasnetsandropes﹣oftenfromillegalfishingvessels. Ghostgearkillsmorethan100000whalesdolphinsandsealseachyearaccordingtoscientificsurveys.Seabirdsandothermarinelifeareincreasinglybeingfounddeadwithstomachsfullofsmallpiecesofplastic.Creatureseatplasticdiscardedintheseathinkingit'sfoodbutthenstarvetodeathbecausetheyarenotfeedingproperly.Othersaretrappedanddieofstarvationorarestrangledorsuffocatedbyghostgear. 1Whatdoestheunderlinedwordinthefirstparagraphprobablymean? A.waste. B.ocean. C.system. D.machine. 2AccordingtothepassagemostoftheGarbageinPacificismadeupof. A.fishingvessels B.dolphinsandseals C.gianttubes D.abandonedfishinggear 3WhydosomecreaturesinTheGreatPacificGarbagePatchdieofstarvation? A.becausetheywerekilledbyGhostgear. B.becausetheyweresuffocatedbyghostgear. C.becausetheydidn'tlikeeatingplastic. D.becausetheyarenotfeedingproperly. 4WhatisthemainideaofthePassage? A.newsaboutthefirstmachinetocleanupoceanplastic. B.reportaboutthedeathofmarinelife C.informationaboutoceanplastic. D.thereasonforinventingamachine.
为研究需要统计了两个变量xy的数据情况如表 其中数据x1x2x3…xn和数据y1y2y3…yn的平均数分别为和并且计 算相关系数r=﹣0.8回归方程为=x+有如下几个结论 ①点必在回归直线上即=b+ ②变量xy的相关性强 ③当x=x1则必有=y1 ④b<0 其中正确的结论个数为
在等差数列{an}中an>0a7=a4+4Sn为数列{an}的前n项和S19=.
在2018年3月开封市第二次模拟考试中某校共有100名文科学生参加考试其中语文考试成绩低于130的占95%人数学成绩的频率分布直方图如图 Ⅰ若成绩不低于130的为特别优秀语文和数学两科都特别优秀的共有3人如果从两课都特别优秀或一科特别优秀的同学中随机抽取2人求这两人两科成绩都优秀的概率. Ⅱ根据以上数据完成列联表并分析是否有99%的把握认为语文特别优秀的同学数学也特别优秀. 参考数据①K2=②
已知向量是单位向量=34且在方向上的投影为﹣則|2﹣|=
10分Livingabroadwillmakeyouadifferentpersonanditwillchangeyouforeverinagoodway.Ilivedabroadformorethanfouryears.1.Herearethemostimportantfourreasonswhyyoushouldstudyabroadandmakethemostofyourstayabroad. Improveyourjobchances.2.HRmanagersvalueinternationalexperiencehighlyascandidateswithexperiencesofstudyingabroadareconsideredtobeadaptableindependentproblem﹣solvingandopen. 3.Gettingoutofyourhomeiscertainlynoteasybutitwillhelpyougrow.Gooutthereandexperiencetheworld.Seeitasanadventurethatyouwilltellyourgrandkidsabout.Sometimesyouhavetopushyourselfandthenyouwillberewardedwiththisawesomefeelingofaccomplishment. Createamemoryofalifetime.Spendingtimeabroadwillbeanadventureandthosememorieswilllastforalifetime.Iknowalotofpeoplethatoncelivedabroadandnoneofthemregretsthetimetheyspentabroad.Yestherewillbedifficulttimes.Whenyoudon'tunderstandthepeoplearoundyoueverythingisforeignandnothingmakessense.Everydaytasksseemlikeamajorproblem.4. Becomeindependent.Livinginaforeigncountryallbyyourselfwillsurelymakeyouindependent.Youareforcedtomakedecisionsbyyourselfasyoudon'thaveotherchoices.5.Showthemthattheywereallsowrongaboutyourbeingamama'sboyorgirl!Itwillfeelgreat! A.Getawayfromhome. B.Improveyourlanguageskills. C.Itwasandstillisthebiggestadventureinmylife. D.Showyourselfyourparentsandfriendsthatyoucandoit. E.Differentcultureshavedifferentvaluestraditionsandcustoms. F.ButIcantellyoufrommyexperiencethatitisdefinitelyworthit. G.Experienceabroadwillgiveyouanadvantageoverotherapplicantsinthejobmarket.
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