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已知函数f(x)=(﹣)ex+a﹣,若对任意x∈(0,+∞),都有2f(x)>﹣xf'(x)成立,则实数a的取值范围是( )
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高三下学期数学《》真题及答案
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.已知函数fx是定义在R.上的可导函数其导函数记为f′x若对于任意实数x有fx>f′x且y=fx﹣1
(﹣∞,0)
(0,+∞)
(﹣∞,e
4
)
(e
4
,+∞)
已知函数fx=2x+k·2-xk∈R.1若函数fx为奇函数求实数k的值2若对任意的x∈[0+∞都有f
已知函数fx的定义域为R.对于任意的xy∈R.都有fx+y=fx+fy且当x>0时fx<0若f﹣1=
已知函数fx=x|x﹣a|a∈R1若a=2解关于x的不等式fx<x2若对任意的x∈04]都有fx<4
已知函数fx=若对任意x∈[1+∞fx>0恒成立试求实数a的取值范围.
已知函数y=fx若存在x0使得fx0=x0则称x0是函数y=fx的一个不动点设二次函数fx=ax2+
已知定义在R.上的函数y=fxf0≠0当x>0时fx>1且对任意的ab∈R.有fa+b=fa·fb.
已知函数fx=ex﹣xe为自然对数的底数1求函数fx在0f0处的切线方程2若对于任意的x∈02不等式
已知函数fx=ex﹣ax﹣1e为自然对数的底数a>0.1若a=1求函数fx在x=0处的切线方程2若f
已知函数fx是-∞+∞上的偶函数若对于任意的x≥0都有fx+2=fx且当x∈[02]时fx=log2
-2
-1
1
2
已知定义在R.上的可导函数fx的导函数为f'x若对于任意实数x有fx-f'x>0且y=fx-1为奇函
(-∞,0)
(0,+∞)
(-∞,e
4
)
(e
4
,+∞)
设函数fxgx的定义域分别为F.G.且F.G.若对任意的x∈F.都有gx=fx则称gx为fx在G.
理科本题满分14分已知函数fx=ex-kxx∈R.Ⅰ若k=e试确定函数fx的单调区间Ⅱ若k>0且对于
已知函数fx=x|x|若对任意的x≤1有fx+m+fx<0恒成立则实数m的取值范围是
(﹣∞,﹣1)
(﹣∞,﹣1]
(﹣∞,﹣2)
(﹣∞,﹣2]
已知函数fx的定义域为R且对任意的实数x导函数f′x满足0 1若对任意的闭区间[ab]R
已知函数fx=2x+k•2﹣xk∈R.1若函数fx为奇函数求实数k的值.2若对任意的x∈[0+∞都有
已知函数fx=alnx-x+1gx=-x2+a+1x+1.1若对任意的x∈[1e]不等式fx≥gx恒
已知函数fx=sinx-xcosxx≥0.1求函数fx在区间[02π]上的最大值2若对任意x∈0+∞
已知函数fx=lg若对任意x∈[2+∞恒有fx>0试确定a的取值范围.
对于函数fx若存在x0∈R.使fx0=x0成立则称x0为fx的不动点.已知函数fx=ax2+b+1x
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Althoughtheideaofzeroemissionnetcarbon﹣positivesustainable可持续developmentwaspromotedworldwidemostcitiesareatalosswhattodoorevensomehaveobjectedtoit.ButinLiuzhouacityinsouthernChinaattitudescouldnotbemoredifferent. TheLiuzhouMunicipalityUrbanPlanningBureauhassignedupItalianarchitectStefanoBoerithefatheroftheforestcitymovementtobuildaself﹣containedcommunityforupto30000people.Heisthego﹣tomanforsuchprojectsthankstothesuccessofhisverticalforeststworesidential住宅的towers.Completedin2014theyremoveupto17.5tonsofsoot煤烟fromtheaireachyearandayearlateroneofthemwasnamedBestTallBuildingWorldwide. TheLiuzhouprojectisamuchmoreambitiousundertakinghowever.Itshomeshospitalshotelsschoolsandofficeswillbebuiltona340﹣acresiteinwhatBoericallsthefirstattempttocreateanurbanenvironmentthatisreallytryingtofindabalancewithnature.Its100speciesofplantlifeareexpectedtoabsorbalmost10000tonsofcarbondioxideand57tonsofpollutantsperyearwhileatthesametimeproducing900tonsoflife﹣givingoxygen. Althoughthearchitectshaven'tpublishedthecostoftheforestcitytheMilantowerscostonlyfivepercentmorethantraditionalskyscrapers. TheconstructionofhisforestcityatLiuzhouissettobeginin2020andthereisstillagreatdealofplanningandresearchrequiredbeforeaprojectedcompletiondatecanbeset.HoweverBoeriremainsoptimisticabouttheprojectandhasconfidenceinthesoundnessofhisvisionIreallythinkthatbringingforestsintothecityisawaytodealwithglobalwarming. 1What'sLiuzhou'sattitudetowardsthesustainabledevelopment? A.Approving. B.Cautious. C.Unfavorable. D.Doubtful. 2WhyisStefanoemployedfortheLiuZhouproject? A.Hevolunteeredtodotheproject. B.Heisafamousarchitectintheworld. C.Heisthefatheroftheforestrecovery. D.Hehasgainedexperienceinsimilarprojects. 3Whatdoestheunderlinedwordtheyreferto? A.Thearchitects. B.Thetwotowers. C.Forestsinthecity. D.Theresidentsofthecity. 4What'sthepurposeofLiuZhouproject? A.Toprovidemorejobs. B.Tobringforestintocity. C.Tosolvehouseshortage. D.Toimprovetheenvironment.
酵母菌进行有氧呼吸和无氧呼吸的共同终产物是
Asafirstresponderyouneverknowwhattypeofsituationyoumightwalkintoorwhoyou'llmeetalongtheway.That'sdefinitelybeenthecaseforJeffreyLanenberga51﹣year﹣oldparamedic急救医务人员since1984. TenyearsintothejobLanenbergreceivedacallthatreportedthatamaninhisearly30shadfallendownintheMallofAmerica.WhenLanenbergandhispartnerarrivedatthescenetheyfoundtheyoungmalefacedownontheground.Hehadgoneunconsciousmakingweakattemptstobreathe.Hiswifestoodbesidehimholdingtheirsmallsoninhorror.Theyquicklyrushedtodefibrillate除颤andcalmthemantokeephimundercontrol.AfterLanenbergdroppedthepatientoffattheneighboringhospitalhethoughtaboutthemanandhisfamilyforalongtime. LanenbergthoughthehadexperiencedeverythingunderthesununtilonerandomvisittoOfficeMaxthreeyearsagowherehemetamanrepeatedlywalkbackandforthwhilestaringathim.Asitturnedoutthemanwasthepatienthehadsaved20yearsearlier. Yougaveme20yearsmorethanIeverthoughtI'dhavethemansaid.HethankedLanenbergrepeatedlyandtoldhimhehadsomeonehewantedhimtomeet.Hesteppedaroundthecornerandreappearedwitha20﹣something﹣year﹣oldman.Lanenberginstantlyknewthatitwasthesonhehadseenstandingbyhismotherallthoseyearsago. ThatdaychangedmylifeLanenbergsaid.Beforethateverythingwasaboutwork…WhenItalktomybeginner﹣trainingclassItellthemyouneverknowtheimpactyoucanhaveonsomeone'slife. 1WhatdidLanenbergdowiththeyoungman? A.Hegavethemanthefirstaid. B.Hecuredthemanatthescene. C.Heonlysentthemantohospital. D.Hetookcareoftheman'swifeandson. 2WhatdidLanenbergthinkoftheencounterwiththeman? A.Itwasunbelievable. B.Itwasacommonroutine. C.Itwasamatterofcourse. D.Itwasadangeroussituation. 3WhywasthemanthankfultoLanenberg? A.Lanenberghelpedbringuphislittleson. B.Lanenbergdonatedtosupporthisfamily. C.Lanenberggavehimthepresenthappylife. D.Lanenbergtaughthissontobeanewdoctor. 4HowdidthemeetingchangeLanenberg'slife? A.Hechangedhisattitudetohisjob. B.Hewasrewardedwithmuchmoney. C.Hegotapromotiontobeateamleader. D.Hetookupteachingworktotrainnewcomers.
LastweekVodafonestartedatestoftheUK'sfirstfull5GserviceavailableforusebybusinessesinSalford.ItispartofitsplantotrialthetechnologyinsevenUKcities.Butwhatcanweexpectfromthenextgenerationofmobiletechnology? Onethingwewillseeinthepreparationforthetestislotsoftrickswiththenewtech.Earlierthisyearoperatorspaidalmost£1.4billionforthe5Gwavelengthsandtocompensateforthatcashtheywillneedtocatchtheeyeofconsumers.InSeptemberVodafoneuseditsbitoftherangetodisplaytheUK'sfirsthologram全息call.TheManchesterCitycaptainStephHoughtonappearedasaholograminNewbury.Itisn'tallhologramshowever5Gwillofferfasterinternetaccess.withOfcom英国通讯管理局suggestingthatvideothattakesaminutetodownloadon4Gwillbeavailableinjustasecond. Thewiderapplicationistosupportconnectedequipmentontheinternetofthings﹣notjusttheinternet﹣enabledfridgethatcanreorderyourmilkforyoubutthenetworkthatwillenabledriverlesscarsanddeliverydrones无人机tocommunicatewitheachother. ProfWilliamWebbhaswarnedthatthetechnologycouldbeacaseoftheemperor'snewclothes.Muchofthespeedincreaseheclaimscouldhavebeenachievedbyputtingmoremoneyinthe4Gnetworkratherthananewtechnology.OtherdifferentvoiceshavesuggestedthatafocusonrollingoutwiderruralbroadbandaccessandaddressingcurrentnetworkcoveragewouldbemorebeneficialtotheUKasawhole. Obviously5Gwillalsobringacosttoconsumers.Itrequiresahandsetforboth5Gand4Gandthefirst5G﹣enabledsmartphonesareexpectedinthecomingyear.Withtheslowpaceofnetworkrolloutsofaritislikelythatconsumerswillendupupgradingtoanew5Gphonewellbefore5Gbecomeswidelyavailableinthenextcoupleofyears. 1WhydoesProfWilliamWebbsaythetechnologycouldbeacaseoftheemperor'snewclothes? A.Heisinfavoroftheapplicationofthenewtechnology. B.5Gwillbringacosttoconsumersintheirdailylife. C.5Ghelpspeoplecommunicatebetterwitheachother. D.Heprefersmoremoneytobespenton4Gnetworks. 2Theunderlinedwordaddressinginthefourthparagraphhastheclosestmeaningto. A.makingaspeechto B.tryingtosolve C.managingtodecrease D.respondingto 3Thelastparagraphindicatesthat. A.it'lltakeseveralyearstomake5GaccessibletothepublicintheUK B.5Gserviceshowshugedevelopmentpotentialandabroadmarket C.customersareeagertouse5Gsmartphonesinsteadof4Gones D.it'sprobablethat5GnetworkrolloutisspeedingupinBritain 4Whatdoweknowaboutthetext? A.Vodafoneissuccessfulinspreadingthe5Gservice. B.StephHoughtonappearedasahologramby4G. C.Theapplicationof5Gwillmakelifemucheasier. D.5GphonesareavailableinruralareasoftheUK.
如图所示的电路中电源电压保持不变R2=20Ω闭合开关S移动滑动变阻器R2的滑片到中点c时电流表的示数为0.4A移动滑片P到最左端a时电流表的示数为0.3A求电源电压和R1的阻值.
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下面是光合作用过程示意图请回答问题. 1光合作用包括两个阶段其中E是在叶绿体的进行该阶段需要D阶段提供的物质是. 2叶绿体的色素分布在.图中A是. 3光合作用发生的部位是. A.叶绿素B.叶绿体C.叶绿体的基粒D.叶绿体的基质
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FromAntiguatoZanzibarfthesespotspromiseanincredibletripfor2019. AntiguaGuatemala Antiguaiswortheverypennybutthatdoesn'tmeanyou'llhavetoemptyyourwalletsaysHudson.Thereareplentyofbudgel﹣carisciousactivities.Itwon'tcostyouacointovisitSantoDomingodelCerroanoutdoorsculpturepark.Wantingsomethingsweet?HeadtoChocoMuseo.Admissionisfreeandsoarethesamples! OdessaUkraine Odessaishavingabitofatourismboomnationwide﹣notthatwe'resurprisedgivenitssandybeachesandpastel﹣coloredbuildings﹣butit'sstillfairlyundertheorderforinternationalaudiences.Youcanalsocountonthisportcityforaffordablefun.TicketstotheOdessaOperaHousestartatamere﹩2! BogotaColombia TravelersonbudgetwillfindColombia'svastcapital.farmoreofabargainandeverybitasfascinatingsaysHudson.It'sfreetovisitMuseodeOroandonSundaysmanyofthebigroadsareclosedtoaccommodatefoodcartsstreetentertainersandpedestrians. Zanzibar Zanzibarattractsvacationerswithitswhitesandbeachesgreenish﹣blueddescolorfulcoralreefsandoceanfrontseaside.OfcoursewanderinginhistoricStoneTownisprettyappealingtoo.Eitherwayyouneedn'tspendapennyinthisamazingplace.It'salsoworthnotingthatJozaniForestistheonlyplaceintheworldyoucan9eeendangeredredcolobusmonkeys. 1Whichofthefollowingrequiresadmissionfee? A.ChocoMuseo. B.StoneTown. C.MuseodeOro. D.OdessaOperHouse. 2WhatisspecialtoZanzibar? A.Whitesandbeaches. B.Colorfulcoralreefs. C.Redcolobusmonkeys. D.HistoricStoneTown. 3Whatdothefourdestinationshaveincommon? A.Theyarecoastalcities. B.Theyareinexpensivetovisit. C.Theywelcomestreetentertainers. D.Theywillmakeyourwalletempty.
一个DNA分子复制完毕后新形成的DNA子链
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Balletisaformalkindofdanceperformancewitharichandinterestinghistory.ThewordballetcomesfromtheFrenchlanguageand1bebasedontheItalianwordballetto.Ballettomeansalittledance.Ballet'searlyrootsbeganinItalyinthelate1400s.ButitwasinFrance2balletdevelopedintotheformweknowtoday. TheFrenchrulerLouistheFourteenthhadabiginfluence3thedirectionofballetinitsearlyhistory.HeruledFranceforseventy﹣twoyears4startin1643.Hestarteddancingasaboyandworkedharddaily. LouistheFourteenthturnedballetintoaformofdancethatreflected5hepowerandinfluence.Ballet'smanyrulesand6extremedetailedmovementsexpressedaperson'spowerandsocialrelations.Thekingmadesurethatballetbecamea7requireforthepeopleofhiscourt.HealsostartedtheRoyalAcademyofDance8importantpeoplecouldlearnthisart.Theaimofthisdancewasself﹣controlorderandperfection. Balletslowlychangedfromadanceattheking'scourttoone9performbyprofessionaldancers.WhenLouistheFourteenthdiedin1715ballet10bringtoodierpartsofEuropeandwasdevelopinginotherways.
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