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已知i是虚数单位,a∈R,则“a=1”是“(a+i)2为纯虚数”的( )
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高三下学期数学《》真题及答案
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设i为虚数单位a∈R若1﹣i1﹣ai为纯虚数则复数1﹣ai的模是
2
1
0
若复数1+2i1+ai是纯虚数i为虚数单位则实数a的值是
﹣2
﹣
2
5.00分已知z为纯虚数且2+iz=1+ai3i为虚数单位则|a+z|=
1
2
已知i为虚数单位若复数1+ai2+i是纯虚数则实数a等于
2
﹣2
已知复数z1=1+aiz2=3+2ia∈R.i是虚数单位若z1z2是实数则a=.
已知z为纯虚数且2+iz=1+ai3i为虚数单位则|a+z|=
1
2
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a∈R.复数z1=2+aiz2=1-2i若为纯虚数则复数的虚部为________.
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
已知i是虚数单位若复数1+ai2+i是纯虚数则实数a等于.
设m∈Rm2+m-2+m2-1i是纯虚数其中i是虚数单位则m=.
已知i为虚数单位a为实数复数z满足z+3i=a+ai若复数z是纯虚数则
a=3
a=0
a≠0
a<0
已知i为虚数单位a为实数复数z满足z+3i=a+ai若复数z是纯虚数则
a=3
a=0
a≠0
a<0
设i为虚数单位a∈R若1+i1+ai是纯虚数则a=
2
﹣2
1
﹣1
已知a∈Ri是虚数单位复数z1=2+aiz2=1﹣2i若为纯虚数则复数的虚部为
i
0
1
已知a∈Ri为虚数单位若1+i1+ai是纯虚数则a=
2
﹣2
1
﹣1
设m∈Rm2+m-2+m2-1i是纯虚数其中i是虚数单位则m=________.
已知复数1+2i1+ai是纯虚数则a的值为.
2016年·陕西全真模拟四若复数1﹣ai2i为虚数单位a∈R是纯虚数则a=
1
﹣1
0
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若复数1+ai2﹣ii为虚数单位a∈R是纯虚数则a的值为
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8分Plasticisusedtomakealargenumberofproductsweuseeverydaysuchasdrinkandfoodcontainerstrashbagsandgrocerybagscupsandchildren'stoysandbottlesforeverythingfrommouthwashandshampootoglasscleaneranddishwashingliquid.Andthat'snotevencountingalltheplasticthatgoesintofurnitureappliancescomputersandautomobiles. Astheuseofplastichasincreasedovertheyearsit'sbecomealargepartofAmerica'ssolidwaste﹣growingfromlessthan1percentin1960tomorethan13percentin2017.AsanexampleofhowandwhyplasticwasteisincreasingtheInternationalBottledWaterAssociationreportsthattheUSconsumed9.67billiongallonsofbottledwaterin2017comparedto9.1billiongallonstheyearbefore.TheUnitedStatesistheworld'sleadingconsumerofbottledwater.Agoodfirststepinreducingplasticwasteisswitchingtoareusablewaterbottle. Recyclingplasticreducestheamountofenergyandresources资源neededtocreateplastic.Researchshowsthatabottleofwaterrequiresabout2000timesasmuchenergytoproduceasthesameamountoftapwater.Recyclingplasticproductsalsokeepsthemoutoflandfills垃圾填埋andallowstheplastictobereusedinmakingnewproducts.Recycling1tonofplasticsaves7.4cubicyardsoflandfillspace.Andlet'sfaceitalotofplasticendsupdirectlyintheenvironmentbreakingdownintotinypieces?pollutingoursoilandwater. Today80percentofAmericanshaveeasyaccesstoaplasticrecyclingprogram.Auniversalnumberingsystemforplastictypesmakesiteveneasier.AccordingtotheAmericanPlasticsCouncilmorethan1800USbusinesseshandleplasticwaste.Inadditionover200000grocerystoresnowserveasrecyclingcollectionsitesforplasticwaste. 1Whatmessagedoesthefirstparagraphmainlyintendtoconvey? A.Plasticproductsarequitecommon. B.Plasticiswidelyusedinourdailylife. C.Whatfunctionsplastichas. D.Whyhumansmakeuseofplastic. 2Accordingtoparagraph2. A.plasticwasteisontheriseinAmerica B.Americanspreferbottledwatertotapwater C.plasticwasteistheleadingtypeofwasteinAmerica D.usingreusablewaterbottlesdoesn'thelpreduceplasticwaste 3Whatbenefitdoesrecyclingplasticmainlybring? A.Ithelpscutdownonpollution. B.Ithelpstomakesoilmorerich. C.Itmakesplasticeasilybrokendown. D.Itproducesnewenergyandresources. 4Whatdothefigureslistedinthelastparagraphsuggest? A.Americanssufferalotfromplasticwaste. B.Americansaregoodatrecyclingplastic. C.RecyclingplasticisconvenientintheUS. D.RecyclingplasticbringsgreatprofitsintheUS.
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下列说法正确的是
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在磁感应强度为B的匀强磁场中一个静止的放射性原子核X发生了一次α衰变.放射出的α粒子He在与磁场垂直的平面内做圆周运动其轨道半径为R.以mq分别表示α粒子的质量和电荷量生成的新核用Y表示.下面说法正确的是
已知三棱锥P﹣ABC的三条侧棱PAPBPC两两互相垂直且PA=PB=PC=a则该三棱锥的外接球的体积为.
某兴趣小组用如图甲所示的实验装置来测物块与斜面间的动摩擦因数.PQ为一块倾斜放置的木板在斜面底端Q处固定有一个光电门光电门与数字计时器相连图中未画.每次实验时将一物体其上固定有宽度为d的遮光条从不同高度h处由静止释放但始终保持斜面底边长L=0.500m不变.设物块与斜面间的动摩擦因数处处相同 1用20分度游标卡尺测得物体上的遮光条宽度d如乙图所示则d=cm 2该小组根据实验数据计算得到物体经过光电门的速度v并作出了如图丙所示的v2﹣h图象其图象与横轴的交点为0.25.由此可知物块与斜面间的动摩擦因数μ= 3若更换动摩擦因数更小的斜面重复上述实验得到v2﹣h图象其图象的斜率将填“增大”“减小”或“不变”.
Createdin1998byCaseyandShelleyBlacktheNorthernLightsWildlifeWolfCenterfocusesonnotonlyrescuingyoungabandonedwolvesbuteducatingthepublic.Unlikeothercentersyoucanactuallywalkwiththewolvesandhaveexcitinghands﹣oninteractionwiththemhere.Andsowegatheredonelatewintermorningtolearnprepareandwalk. ScrappyandFloraourwolvesthatdaywerebroughttothecenterwhenonlyafewdaysold.Theylivedinthehousewithusforthefirstseveralmonths.WetreatedthemlikehumanbabiesfedthemandsleptwiththemsaidShelley.Sotheyaretotallyusedtopeople.Howeverthesearewildanimals.ForthatreasonShelleyandCaseyexplainedthewalkistotallyonthewolf'sterms.Wedon'tapproachthembutiftheycomeuptouswecantouchthem. Withallthisinmindweheadedforthewoods.WewerewalkingonaloggingroadwhensuddenlyFloraall60poundsofherhurrieduptomeandraiseduponherlegs.Shewasalmostastallasme.Assheleanedinputherhugemuddypawsonmyshouldersandsniffedmyfaceapparentlyshewassayinghelloinwolftalk. WewalkedfarthermaybehalfamilewhileScrappyandFloradashedinandoutofthewoodsstoppingtooccasionallyrollinthesnowdigforthisorthatandjustplay.Thenweallheadedintothetreestoapicturesquestreamwherethewolvessplasheddrankandhadagreattime. Onecouldpointoutthatthiswholeadventurewasstagedandquiteartificial.ButthepurposeCaseyandShelleysaidistoexplainthewolves'placeintheenvironmentandprimarilytoletpeopleknowwolvesdon'thavetobeuniversallyfeared﹣theyreallydon'thidesecretlyinthewoodsjustwaitingtoeatpeoplebutthey'dratheravoidpeopleforthemostpart. 1HowistheNorthernLightsWildlifeWolfCenterdifferentfromothers? A.Ittrainsandeducateswildwolves. B.Itaimstorescueyoungabandonedwolves. C.Itraiseswolvesforcommercialpurposes. D.Itallowsvisitorstotakeawalkwithwolves. 2WhatcanbeinferredfromShelleyandCasey'sexplanationinParagraph2? A.Thewalkcanbepotentiallydangerous. B.Thewolveshavelostalltheirwildness. C.Peopleshouldgetclosetothewolvesactively. D.Thewolvescanreadpeople'smindlikehumanbabies. 3WhydidFlorabehavelikethatwhenshesawtheauthorontheloggingroad? A.Toexpresscuriosity. B.Toshowfriendliness. C.Toattractattention. D.Toseekcompanionship. 4WhydoCaseyandShelleyorganizesuchanadventure? A.Toadvertisethecenter. B.Topublicizewolfhunting. C.Topromoteenvironmentalprotection. D.Toclarifysomeconventionalviewsofwolves.
已知a1=1an=nan+1﹣ann∈N*则数列{an}的通项公式为.
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. LastmonthourclassorganizedahikingalongtheChaobaiRiverwhichrunthroughHebeiBeijingandTianjin.MuchtomydisappointIfoundtheriverwasseriouspolluted.AtthatmomentIwasdeterminedtodowhatIcouldprotectit.Firstundermyteacher'shelpIusedtheequipmentsfromtheschoollabtotestthequalityoftheriverwater.ButthenIusedthedataIhadcollectedittoanalyzethepollutionofthewater.FinallyIwriteareportonthepollutionoftherivertothelocalgovernment.IalsogaveapresentationinclasswhereIsuggestedthatwemustmakesmallchangestoprotectourwaterresources.
30分WhenCharlesBarkley'smotherpassedawayBarkley'shometowncametothefuneral.Butan1guestalsocame.Hewasn'tabasketballplayerorfromBarkley'shometown.More2hewasmydad﹣ascientist. Mydadsaidhe3aboutBarkleylongbeforehemethim.Wheneverwe4dinnerpartieshewouldtalkaboutBarkley.Basketballhasneverbeenmything.I5somekeywordsintoasearchengineto6somethingaboutBarkley.Heseemedprettyfamousand7notlikeanyonewhowouldbefriendswithmydad. Butthefriendshipwasreal. Mydad8madeaslideofphotosofhimandBarkleytogetherforourcommunity'sChineseNewYearparty﹣totallyirrelevanttothe9.Iaskedhimwhatmadethembecomefriends. AsanAsianintheU.S.wehadagood10hesaid.Weagreeonmanyviews. Theybelievedthecoloroftheirskindidn't11. ButonaSundayafternoonmydadpassedaway.Everyonewas12asBarkleyattended thefuneral.Itgivesmegreat13andjoytoknowIwasafriendofhisBarkleysaid.Justhearingabouthimatthe14whathehadachievedandwhathewastryingtohelpothers 15touchedmeI16hewouldbeknowntomanypeople. Atthefuneralpeople17memoriesofmydad.IrealizethatevenafterhepassedawayIwouldcontinueto18thingsabouthim. ThestoryofhisfriendshipwithBarkleywasnotjusta19withafamousperson﹣itthrewlightonthe20ofthisworld. 1A.frequent B.unexpected C.average D.unwelcome 2A.specifically B.importantly C.carefully D.strictly 3A.cared B.worried C.thought D.knew 4A.held B.organized C.attended D.arranged 5A.read B.forgot C.sent D.typed 6A.findout B.applyfor C.talkabout D.pickup 7A.potentially B.accidentally C.deliberately D.certainly 8A.still B.also C.even D.already 9A.experience B.holiday C.player D.friendship 10A.chance B.conversation C.argument D.choice 11A.bum B.differ C.matter D.shine 12A.astonished B.thrilled C.annoyed D.disappointed 13A.moments B.memories C.relief D.comfort 14A.meeting B.hometown C.party D.funeral 15A.accomplish B.contribute C.develop D.gain 16A.wished B.declared C.suspected D.confirmed 17A.improved B.refreshed C.shared D.lost 18A.spread B.leam C.obtain D.mourn 19A.connection B.coincidence C.phenomenon D.relationship 20A.benefits B.responsibilities C.possibilities D.varieties
25分假定你是李华你的新西兰朋友Terry没有进入学校唱歌比赛的决赛感到非常伤心.请你给他写一封email内容包括 1.表示安慰 2.给予鼓励 3.提出希望. 注意1.词数100左右 2.可以适当增加细节以使行文连贯.
设函数fx=ax2+blnx﹣x已知曲线y=fx在点1f1处的切线与直线x﹣y+1=0垂直. 1求a的值 2求函数fx的极值点.
室温时用0.100mol•L﹣1AgNO3溶液滴定50.0mL0.0500mol•L﹣1NaCl溶液的滴定曲如图所示[pCl=﹣lgCl﹣].下列有关描述错误的是
在真空中某点固定一个带负电荷的金属小球A可视为点电荷所带电量Q=1.0×10﹣5C在离它10cm处放置另一个带负电的检验电荷B以下描述正确的是
在△ABC中角ABC所对应的边分别为abc且满足=•=3. Ⅰ求△ABC的面积 Ⅱ若b+c=6求a的值.
物质的结构性质和用途之间有着非常密切的关系.下列有关物质的性质与用途的因果对应关系错误的是
10分Makingabudgetcanbequiteasatisfyingprocess.Afterdrawingoneup?You'llprobablyfeelproudthatyou'vecontrolledyourfinances.Howeverdrawingupyourbudgetisn'tthemostimportanttaskwhenifcomestomanagingyourmoneysuccessfully.1. Ifyou'reoneofthemanypeopleinBritainwithmorethanonebankaccountusingseveralalongsideoneanothercouldhelpyoustayincontrolofyourspending.2.Thatcanhelpyouavoidoverspendinginasinglearea. 3keepaneyeonyouraccountseachmonth.Whetheryoureceiveyourregularbankstatementsandbillsthroughthepostoronlinemakesureyoucheckthem.Theycantellyouwhereyoumightbeoverdoingitandshouldinspireyoutocutbackimmediatelyifnecessary.Besidesyou'relikelytopickupanyproblemsastheyarise. Makinganoteofallyourspendingforafewweeksisanotherwaytocheckthatyourmoneyreallyisgoingwhereyou'dlikeitto.4butifyoutendtospendusingcashratherthanacreditcardyouwontbeabletotrackwhereyourmoneyisgoingsimplyfromlookingatyourbankstatementsandbills. Asyourpersonalcircumstanceschangeyourbudgetwillneedtobechangedtoo.5.Whileitmayseemlikeachancetoloosenupyourpursestringsslightlyfailingtotakeaccountofanincomeriseinyourbudgetcouldmeanyoudon'ttrulymakethemostofit. A.Ifyouwantyourbudgettostaybalanced B.It'lltakeafewmonthstogetusedtobudgeting C.Itmayseemtiresometowriteeverythingdown D.Divideupyourincomeeachmonthintoseparateaccounts E.Onceyou'velinkedallyouraccountsyoucancreateabudget F.Gettingapromotionorpayriseshouldmeanyouremakeyourbudget G.Thekeytoeffectivebudgetingisstickingtothespendingplanyou'vemade
工业废水中含有的Cr2O72﹣和CrO42﹣会对水体产生很大的危害因此这种工业废水必须净化处理.一种处理含铬废水的工艺流程如下 ①中反应为2CrO42﹣黄色+2H+⇌Cr2O72﹣橙色+H2O. 下列说法正确的是
如图所示带电小球a由绝缘细线PM和PN悬挂而处于静止状态其中PM水平地面上固定一绝缘且内壁光滑的圆弧细管道GH圆心P与a球位置重合管道底端H与水平地面相切一质量为m可视为质点的带电小球b从G端口由静止释放当小球b运动到H端时对管道壁恰好无压力重力加速度为g.在小球b由G滑到H过程中下列说法中正确的是
如图直三棱柱ABC﹣A1B1C1中DE分别是ABBB1的中点. 1证明BC1∥平面A1CD 2设AA1=AC=CB=2AB=2求三菱锥C﹣A1DE的体积.
ABCDE是元素周期表中原子序数依次增大的前四周期元素.A与B同周期且A元素原子核外s能级有1个未成对电子B元素的原子核外p电子比s电子少1C元素的原子序数比B元素多1D元素的原子价电子有6个未成对电子它的一种化合物常用于检验酒驾E元素的原子价电子有4个未成对电子.请回答下列问题 1第一电离能介于A和B之间的同周期元素有填元素符号. 2B元素的最高价氧化物的水化物在水溶液中能完全电离电离所得阴离子的空间构型为.写出2种与该阴离子互为等电子体的微粒的化学式.画出基态D原子的价电子排布图. 3C元素对应的简单氢化物的沸点明显高于同族其他元素对应的简单氢化物其原因是. 4元素D可以形成的配合物如图1所示. ①该配合物中碳原子的杂化类型为. ②该配合物中所含化学键的类型不包括填字母. a.极性共价键b.非极性共价键c.配位键d.离子键e.金属键f.σ键g.π键 5元素E的单质和氮气在640℃可发生置换反应产物之一的晶胞结构如图2所示该反应的化学方程式为.若该晶体的密度是ρg•cm﹣3则两个最近的E原子间的距离为cm.用NA表示阿伏加德罗常数的值
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