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已知函数，． （1）若，求函数f（x）的值； （2）求函数f（x）的值域．
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高一下学期数学《》真题及答案
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如图抛物线y＝ax2+bx+c的顶点坐标为1n与x轴交于点A﹣10与y轴的交点在0203之间包含端点则下列结论 ①3a+b＜0 ② ③对于任意实数ma+b＞am2+bm总成立 ④关于x的方程ax2+bx+c＝n﹣1有两个不相等的实数根． 其中结论正确的个数为
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InthestorytoldbytheRomanpoetOvidPygmalionisasculptorwhofallsinlovewithastatuehehascreated.BernardShawborrowedthethemeforhisplayPygmalion﹣laterturnedintothemusicalMyFairLady﹣﹣﹣inwhichProfessorHenryHigginschangestheCockneyflowergirlElizaDoolittleandlovesherevenasheteachesherhowtospeakproperEnglish. PsychologiststoohavepickedupthethemeresearchingwhattheycallthePygmalioneffect.ThefindingassocialpsychologistRobertRosenthalputsitisthatwhatonepersonexpectsofanothercancometoserveasaself﹣fulfilling应验的prediction.RosenthalandhiscoauthorLenoreJacobsoncreatedthetermtodescribetheamazingresultsofanexperimenttheycarriedoutinaCaliforniaschoolin1965.Studentstookatestthatwassaidtobeabletoidentifygrowthspurters﹣﹣﹣thosewhoweretomakegreatprogressacademically.Teachersweregiventhenamesofpupilswhowereabouttoprogressintellectually﹣﹣﹣andsureenoughthesestudentsshowedasignificantlygreatergaininperformanceovertheirclassmateswhentestedagainattheendoftheyear. Buthereisthethingthespurterswereactuallychosenatrandom.TheonlydifferencebetweenthemandtheirclassmatesRosenthalwriteswasinthemindoftheteachers.Andyettheexpectationsheldinthemindoftheteacherscanmakeabigdifference. Justhowdohighexpectationspromotegreaterachievement?It'snotsomemagicalact.Ratheritishigherexpectationsthatleadteacherstoactdifferentlyinsomespecialwaystoencouragestudents.Sobychangingourbehaviorandbelievingourstudentshavegreatpotentialwecanhelpourstudentsrealizetheirpotential. 1TheauthoroftheplayPygmaliongotinspirationfromC. A.themusicalMYFairLady B.somepsychologists'research C.aRomanstorytoldbyOvid D.aprofessor'slovestoryinEngland 2Whydidthespurtersmakegreatprogressintheexperiment?C A.theywerechosenatrandom B.theyweremoreconfidentthantheirclassmates C.theyreceivedhighexpectations D.Therewassomemagicinteachers'behavior 3Theexperimentconductedin1965A. A.isanexampleofthePygmalioneffect B.improvedallthestudents'grades C.hadnormalresultspredictedbyteachers D.identifiedgrowthspurterssuccessfully 4Forwhomwasthetextprobablywritten?A A.Teachers B.Students C.Researchers D.Writers
御都学校九年级7个班师生举行毕业文艺汇演每班3个节目有歌唱与舞蹈两类节目统计后发现唱歌类节目数比舞蹈类节目数的2倍少3个． 1九年级师生表演的歌唱与舞蹈类节目数各有多少个 2该校七八年级师生有小品节目参与在唱歌舞蹈小品三类节目中每个节目的演出平均用时分别是4分钟6分钟8分钟预计所有演出节目交接用时共花15分钟．若从2000开始2230之前演出结束问参与表演的小品类节目最多能有多少个
将AB两位篮球运动员在一段时间内的投篮情况记录如下 下面有三个推断①当投篮30次时两位运动员都投中23次所以他们投中的概率都是0.767②随着投篮次数的增加A运动员投中频率总在0.750附近摆动显示出一定的稳定性可以估计A运动员投中的概率是0.750③当投篮达到200次时B运动员投中次数一定为160次．其中合理的是．
WalkthroughtheAmazonrainforesttodayandyouwillfinditsteamywarmdampandthick.Butifyouhadbeentherearound15000yearsagoduringthelasticeagewouldithavebeenthesame?Formorethan30yearsscientistshavebeenarguingabouthowrainforestsmighthavereactedtothecolddryclimateoftheiceagesbuttillnownoonehasreachedasatisfyinganswer. RainforestsliketheAmazonareimportantformoppingupCO2fromtheatmosphereandhelpingtosolveglobalwarming.CurrentlythetreesintheAmazontakeinaround500milliontonsofCO2eachyearequaltothetotalamountofCO2givenoffintheUKeachyear.ButhowwilltheAmazonreacttothefutureclimatechange?IfitgetsdrierwillitsurviveandcontinuetodrawdownCO2?Scientistshopethattheywillbeabletolearninadvancehowtherainforestwillmanageinthefuturebyunderstandinghowrainforestsreactedtoclimatechangeinthepast. Unfortunatelycollectinginformationisincrediblydifficult.Tostudythepastclimatescientistsneedtolookatfossilizedpollen花粉keptinlakemudGoingbacktothelasticeagemeansdrillingdownintolakesediments沉淀物whichrequiresspecializedequipmentandheavymachinery.Thereareveryfewroadsandpathsorplacestolandhelicoptersandaeroplanes.Riverstendtobetheeasiestwaytoentertheforestbutthisstillleavesvastareasbetweentheriverscompletelyunsampled未取样.SofaronlyahandfulofcoreshavebeendrilledthatgobacktothelasticeageandnoneofthemprovideenoughinformationtoprovehowtheAmazonforestreactstoclimatechange. 1Howdoscientistsstudythepastclimatechange? A.Bypredictingtheclimatechangeinthefuture. B.Bydrillingdowndeepintolandsediments. C.Byanalyzingfossilizedpolleninlakemud. D.BytakingsamplesfromriversintheAmazon. 2Whyisitdifficulttocollectinformationaboutthepastclimatechange? A.Becausescientistscan'tfindproperequipmentandmachinery. B.Becauseitisverydifficulttoobtaincompletesamples. C.Becausehelicoptersandaeroplaneshavenoplacetoland. D.Becausenoneofthecoresprovideanyinformation. 3Whereisthepassagemostprobablytakenfrom? A.Amedicaljournal. B.Anewsreport C.Atravelbrochure. D.Asciencemagazine. 4Thebesttitleforthetextmaybe. A.SecretsoftheRainforest B.ClimatesoftheAmazon C.TheHistoryoftheRainforest D.ChangesoftheRainforest
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