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已知直线方程2x﹣y+c=0的一个方向向量可以是( )
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高三下学期数学《》真题及答案
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已知直线l1的方向向量a=13直线l2的方向向量为b=-1k若直线l2过点05且l1⊥l2则直线l2
x+3y-5=0
x+3y-15=0
x-3y+5=0
x-3y+15=0
直线=3的一个方向向量可以是.
已知方程2x2+9x+8=0求作一个一元二次方程使它的一个根为原方程两根和的倒数另一个根为原方程两根
已知x=-2是一元二次方程x2+2x+a=0的一个解则此方程的另一个解是
x = 0
x = - 2
x = 2
x = - 14
已知直线l1的方向向量是a=24x直线l2的方向向量是b=2y2若|a|=6且a·b=0则x+y的值
-3或1
3或-1
-3
1
设回归方程yc=2+3x当x=5时yc=________当x每增加一个单位时yc增加________
已知关于x的方程2x2+kx-1=0.1求证方程有两个不相等的实数根2若方程的一个根是-1求k值及另
已知x=﹣1是关于x的方程2x2+ax﹣2=0的一个根则a=______.
3.00分已知直线经过两条直线l1x+y=2l22x﹣y=1的交点且直线l的一个方向向量=﹣32则
﹣3x+2y+1=0
3x﹣2y+1=0
2x+3y﹣5=0
2x﹣3y+1=0
.已知关于x的方程x2+2x﹣k2=0的一个根为1则k=__________.
已知直线l13x+4y﹣2=0和l22x﹣5y+14=0的相交于点P..求1过点P.且平行于直线2x
.已知一个圆经过直线l2x+y+4=0和圆Cx2+y2+2x﹣4y+1=0的两个交点且有最小面积求此
若直线l过点34且12是它的一个法向量则直线l的方程为.
2x+y-11=0
x+2y-11=0
x+2y=0
2x+y-1=0
已知直线方程2x﹣y+c=0的一个方向向量可以是
(2,﹣1)
(2,1)
(﹣1,2)
(1,2)
与直线y=﹣2x平行的直线可以是.写出一个即可
已知x=﹣1是关于x的方程2x2+ax﹣a2=0的一个根则a=.
已知关于x的方程2x2+kx-1=01求证方程有两个不相等的实数根2若方程的一个根是-1求另一个根及
直线2x﹣3y+10=0的法向量的坐标可以是
(﹣2,3)
(2,3)
(2,﹣3)
(﹣2,﹣3)
已知x=-1是关于x的方程2x2+ax-a2=0的一个根则a=____________.
已知关于x的方程2x2+kx﹣1=0.1求证方程有两个不相等的实数根2若方程的一个根是﹣1求另一个根
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ConfidenceComesFromTreatingOthersAsEquals There'sbeenrecentdiscussionoverChineseattitudestowardforeignerscausedbyanotherquarrelbetweenaforeignerandataxidriver.AccordingtothestudiesdescribedintheOxfordHandbookofChinesePsychologyChinesehavelowerself﹣confidencecomparedtoWesterners.YetdoestheresultstillapplytotheChinesepeopletoday? Yesandno.ForthemomentdifferentattitudestowardforeignerscanstillbefoundinChina'ssocietywithsomedisplayinglowself﹣confidencelikeForeignersareawesome令人敬畏的andWesterncountriesareawesome.Weshouldrespectthemandbeaspoliteaspossibleandshouldn'tletthemlookdownonusandafewunfriendlyopinionssuchasSomeforeignersarerudeanddisrespectfulandtheirlevelofcivility礼貌isfarbehindChina. Chineseusedtobelackinginself﹣confidence.ItmightstartfromthemodernhistoryafterthefailureintheOpiumwarsandthefollowinghumiliation耻辱ofbeingbullied被欺负andbroughttotheirkneesbyWesternguns.Andthedarkhistoryisstilltosomeextentaffectingourmentality心态today. ForsometimetheWesternworldrepresentsthebestofeverythinginsomeChineseeyes.Butourstateofmindisgraduallychanging.WhenaskedWhatmakesyoufeelproudofyourcountry?inschoolclassesinChinaanswersvaryfromtheWorldExpototheOlympicGamesfromathletestoastronautsfromthemushroomingskyscraperstobusymetropoliseswhichhaveallfilleduswithgrowingself﹣confidence. WhileansweringthequestionSinceChinaissogoodtodayandChinesepeoplearemoreconfidentwhyareanincreasingnumberofChineseemigratingabroad?ZhangWeiweiaprofessoratFudanUniversityrepliedthatatleast70percentofChinesemigrants移民becomemorepatriotic爱国的afterleavingtheirhomecountrynomatterwhethertheyhavebecomeanaturalizedcitizenofanothernationornot.Suchresultandexperiencesaremuchmoreconvincingandhavebettereffectthandozensofpatrioticeducationclasses. Thereisnoreasonforusnottobeself﹣confident.Weliveintheworld'ssecond﹣largesteconomy.Chinesenetfinancialassetspercapita人均纯金融资产andthepurchasingpowerofpeoplehaveseenasharprisewithmoreandmorepeoplestartingtopurchaseworksofartinsteadofonlynecessities.Theseallindicatearisingstandardoflifeandself﹣confidence. NeverthelessthepointofthechangingattitudestowardourselvesorothercountriesisnotrealizingothernationsarebetterorworsethanChinabuttreatingthemlikehowwetreatourfellowChinese.Thatiswhatconfidencemeansnotbeingcondescending屈尊notworshipingbutlookingeachotherintheeyewithtrustandrespect. 1AccordingtothetextwhataretheChineseattitudestowardforeignerstoday? A.Theyhavevariousattitudestowardforeigners. B.Theythinktheforeignersarealwaysrude. C.Theyalwaysspeakhighlyoftheforeigners. D.Theybelieveforeignersarejustcommonpeople. 2Chineseusedtolackself﹣confidencebecause. A.Theythoughttheforeignersweremysterious. B.Theyusedtothinkthemselveslesspowerful. C.Theyweredeeplyinfluencedbythedarkhistory. D.Theyoncebelievedforeignerswereawesome. 3AccordingtoZhangWeiweimostChinesemigrants. A.desiretobeacitizenofanothernation B.developastrongerlovefortheirhomecountry C.areunwillingtoreturntotheirmotherland D.serveasbadexamplesinpatrioticeducation 4What'sthemainideaofthepassage? A.Chineseshouldbeproudofthegreatachievementoftheircountry. B.Chinesehaveenoughconfidencetomakegreaterprogress. C.Chinesehavealowerself﹣confidencefacedwithforeigners. D.Chineseshouldbeconfidentandtaketheforeignersasequals.
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.答案应写在答题卡上2每处错误及其修改均仅限一词 3.只允许修改10处多者从第11处起不计分. We'relivinginaworldwherewecanneverstresstheimportantofsharingtoomuch.Bysharingwecanoftengreatreduceoursadnessanddoubleourhappiness. Whenitcametothistopicmemoriesfloodintomymind.TherewasatimewhenIcaughtinthesadnessofnotpassinganimportantexam.MyworldturnedgrayandIdidn'tfeelinterestedinsomethinguntilmybestfriendcameuptocomfortme.EncouragedandmovedbyhiskindnessIsharedmytroublewithhimthatrelievedmesoon.LittlebylittleIregainedmyconfidence.ThefollowedmonthswitnessedmyeffortsandIfinallymadeagreatprogressinotherimportantexams. Asyoucanseewhichwassharingwithmyfriendthathelpedmeoutofthatdarktimeandbringbackmyconfidence.Sharingisbeautifulnotonlyphysicallybutalsomentally.
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如图在边长为1的正方形网格中粗实线表示一个三棱锥的三视图则该三棱锥的体积为.
已知在等比数列{an}中a1=1且a2是a1和a3﹣1的等差中项. 1求数列{an}的通项公式 2若数列{bn}满足bn=2n﹣1+ann∈N*求{bn}的前n项和Sn.
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已知数列{an}为等差数列Sn为其前n项的和.若a1+a3=6a4=7则S5=.
WhilemanycountrieslovetheirteaUKcitizensareparticularlyproudofbeingteapeople.TheaverageUKcitizenconsumesnearly2kilogramsofteaeachyear. TeaonlymadeitswaytoEnglandinlargequantitiesinthefirstyearsofthe17thcentury.TeafromChinaandafewotherAsiancountrieswasbeingsoldmorewidelyinEnglandatthattime.Thenteawasgettingmoreandmorepopularamongdifferentsocialclasses. Therearemanyvarietiesoftea.BlackteamixturesarestillthemostcommontypedrunkintheUK.Blackteaisdarkincolourbecausetheleaveshavebeenallowedtooxidize氧化beforedrying.Thisiswhyweusuallyserveitwithmilkalthoughitisnotuncommontodrinkitblackorwithlemon.Youmaystillfindteamadewithloosetealeavesservedupinapotandpouredintothebestchinacupswithsaucers茶托forvisitors. TeaisstillalargepartofdailylifeintheUKtodaybutitseemstobeonthedecrease.TheamountofteasoldintheUKfellbymorethan10%inthefiveyearsleadingupto2002andhasbeendroppingeversince.Teasalesfellby6%in2014aloneandmostrestaurantsreportsellingmorethantwiceasmanycupsofcoffeeastheydotea.Morethan£1billionwasspentoncoffeeinhighstreetstoresin2013morethantwicewhatwasspentonteabags. Stillwhatgoesaroundcomesaroundit'ssuretobecomefashionableagain. 1Whichofthefollowingistrueaccordingtothefirstthreeparagraphs? A.TeamadeitswaytoEnglandintheearlyyearsofthe16thcentury. B.TheUKusuallyservesblackteawithlemon. C.TeafromChinawasbeingsoldmorewidelyinEnglandnow. D.UKcitizenstakeprideinbeingteapeople. 2Whatcanweinferfromthefourthparagraph? A.Teasalesfellby6%in2014alone. B.Since2002thesalesofteahasbeenonthedecrease C.In2013themoneyspentonteawas£3billion D.Mostrestaurantlikesellingteathancoffee. 3Whatdoestheunderlinedsentencemeaninthelastparagraph? A.Itcanneversucceedagain B.Theteacanbecomepopularagain C.Coffeeismorepopularthantea D.Theteaisbecominglesspopular 4Whatistheauthor'spurposeinwritingthetext? A.TointroduceteaintheUK B.Toshowtheauthor'spreferencefortea C.Tointroducethefunctionsoftea D.TocompareteainChinaandUK
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设θ为第二象限角若tan=则sinθ•cosθ=.
已知sin+α=则cosπ﹣2α的值等于
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设集合A={x|x>0}B={x|x2﹣5x﹣14<0}则A∩B等于
若实数xy满足约束条件且目标函数z=x+y的最大值等于
若0<x1<x2<1则
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已知向量=12=x﹣2且⊥则|+|=
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已知{an}为等差数列a1+a3+a5=18a2+a4+a6=24则a20等于
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