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若曲线f(x)=aex+e﹣x在点(0,f(0))处的切线与直线x+3y=0垂直,则函数f(x)的最小值为 .
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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=x﹣alnxa∈R..1当a=2时求曲线y=fx在点A.1f1处的切线方程2若对于x∈
已知函数fx=gx=alnxa∈R.若曲线y=fx与曲线y=gx相交且在交点处有相同的切线求a的值及
设函数fx=ax-曲线y=fx在点2f2处的切线方程为7x-4y-12=0.1求fx的解析式2证明曲
设函数fx=x3+a-1x2+ax若fx为奇函数则曲线y=fx在点00处的切线方程为
y=-2x
y=-x
y=x
y=2x
如何求曲线fx在点x0fx0处的切线方程
下列说法正确的是
若f′(x
0
)不存在,则曲线y=f(x)在点(x
0
,f(x
0
))处就没有切线
若曲线y=f(x)在点(x
0
,f(x
0
))处有切线,则f′(x
0
)必存在
若f′(x
0
)不存在,则曲线y=f(x)在点(x
0
,f(x
0
))处的切线斜率不存在
若曲线y=f(x)在点(x
0
,f(x
0
))处没有切线,则f′(x
0
)有可能存在
已知函数fx=alnx+其中a为常数.1若a=0求曲线y=fx在点1f1处的切线方程2讨论函数fx的
设函数fx=ax2+bx+kk>0在x=0处取得极值且曲线y=fx在点1f1处的切线垂直于直线x+2
曲线fx在点x0fx0处的切线与曲线过某点x0y0的切线有何不同
定义在R上函数fx满足fx=f﹣xf2+x=f2﹣x若曲线y=fx在x=1处的切线方程为x+y﹣3=
x+y﹣3=0
x﹣y﹣2013=0
x﹣y﹣2015=0
x﹣y+2017=0
设fx是偶函数若曲线y=fx在点1f1处的切线的斜率为1则该曲线在点-1f-1处的切线的斜率为___
已知a<0曲线fx=2ax2+bx+c与曲线gx=x2+alnx在公共点1f1处的切线相同.Ⅰ试求c
已知函数fx=ex+axgx=exlnx.e≈2.71828.1设曲线y=fx在x=1处的切线与直线
设函数fx=ex+gx.若曲线y=gx在点P0g0处的切线方程是y=2x+1则曲线y=fx在点Q0
y=2x+1
y=2x+3
y=x+2
y=3x+2
导数的几何意义导数f'x0的几何意义就是曲线y=fx在点P.x0fx0处的切线的斜率即k=f'x0相
若连续函数y=fx在x0点不可导则曲线y=fx在x0fx0点没有切线.
已知a是实数函数fx=x2x-a.1若f′1=3求a的值及曲线y=fx在点1f1处的切线方程.2求f
设函数fx=a∈R.Ⅰ若fx在x=0处取得极值确定a的值并求此时曲线y=fx在点1f1处的切线方程Ⅱ
下列说法正确的是
若f ′(x
0
)不存在,则曲线y=f(x)在点(x
0
,f(x
0
))处就没有切线
若曲线y=f(x)在点(x
0
,f(x
0
))处有切线,则f ′(x
0
)必存在
若f ′(x
0
)不存在,则曲线y=f(x)在点(x
0
,f(x
0)
)处的切线斜率不存在
若曲线y=f(x)在点(x
0
,f(x
0
))处的切线斜率不存在,则曲线在该点处就没有切线
已知a>0fx=ax2-2x+1+lnx+1l是曲线y=fx在点P.0f0处的切线.求切线l的方程.
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10分Forcollegegraduatesitisofvitalimportancetowriteapplicationletterswell.1Itshouldstateclearlythejobyouwantandshouldtellwhatyouhavedone.Itshouldbesimplehumanpersonalandbriefwithoutleavingoutanynecessaryfacts. Inwritingaletterofapplicationkeepinmindthatthethingsapossibleemployerismostlikelytowanttoknowaboutareyourqualificationsyourachievementsandyouraims.2Ifthefirstfewsentencesfailtowinthereader'sattentiontherestofthelettermaynotbecontinuedatall.Trytokeyyouropeningremarkstotheneedsorinterestsoftheemployernottoyourownneedsordesires.ForexampleinsteadofbeginningwithIsawyouradvertisementintoday'snewspaperyoumightsayIhavemadeacarefulstudyofyouradvertisingduringthepastsixmonthsorIhavemadeasurveyinmyneighborhoodtofindouthowmanyhousewivesuseyourproductandwhytheylikeit. 3Beclearaboutthekindofjobforwhichyouarenowapplying.Collegegraduateslookingfortheirfirstpositionsoftenaskwhattheycanprovideinaletterandwhatifemployerswarnexperiencewhichnaturallynobeginnerhas.4 Itisimportanttowriteagoodstrongclosingforyourletter.Makeaspecificrequestforanintervieworgivethepossibleemployersomethingdefinitetodoorexpect.5Thatmakesiteasierforapossibleemployertogetintouchinyou. A.Hereareafewsuggestionsforyoutoprepareyourselfbetterforyourinterview. B.Anexcellentideaistoencloseastampedself﹣addressedenvelopewithyourletter. C.Theansweristhateverythingyouhaveeverdoneisexperience. D.Don'tbeafraidofbeinganewhand. E.Trytoavoidwritingingeneral. FThepurposeofaletterofapplicationistohelpyoutosellyourself. G.Theopeningparagraphisperhapsthemostimport.
下列物质不能与铁发生反应的是
30分Istoodonmygrandmother'sfrontporchwithmyson.Hehadabottleofbubbles.Youknowthe1it'sbasicallysoapywaterwithaplasticlooponeachend.Youdiptheloopinthebottle pullitoutandblowittomakebubbles.Mysonunderstoodtheprinciplebutwas2tryingtoblowbubbles.He3dipanddipandblowandblowbutalasnobubbles.He4methebottleandloopandaskedmeDaddycanyoumakebubbles? Ihadn'tblownbubblesinyears.Iama5byeducationfairlywell﹣trainedinsurfactant活性剂technology.Ihave6severalshampoossoIunderstandsurfacetensionandrelatedfoaming发泡沫characteristicsofsurfactants.Allthatknowledgeis7uselesswhentryingtoblowbubblesfromaloop8withsoapywater.Iwashavingno9successthanmyson.Idippedandpuffedstillnobubblesthesoapyfilmontheloopwouldjustpopwithout10anybubbles. Afterseveralfruitless111changedstrategies.12puffingontheloopofsoapywaterIgently13onit.Mysonscreamedwithdelightasabigbeautifulbubbleformedand14away.Hegrabbedtheloopdippedandblew.Nobubbles.I15tohimSonyoucan'tblowhard.Youmusteversogentlybreatheonthelooptomakebubbles.Hecontainedhisurgent16tomakebigbubblesbyblowinghardand17myadvice.Bigbubbles. Therearesomethingsthatyoucangetwith18forcebutotherthingslikeloveorrespectonly19thegentlenessofasoftbreath.The20somethingistohigherspiritthemoreitislikebubblesitcan'tbeforced.Blowbeautifulbubblesbreatheeasy. 1A.type B.color C.size D.liquid 2A.excitedly B.willingly C.quickly D.vainly 3A.could .B.would C.might D.should 4A.handed B.lent C.sent D.brought 5A.teacher B.doctor C.chemist D.physicist 6A.bought B.designed C.developed D.used 7A.nearly B.hardly C.partly D.completely 8A.filled B.loaded C.dotted D.crowded 9A.less B.much C.more D.little 10A.flying B.forming C.keeping D.taking 11A.attempts B.performances C.experiments D.adventures 12A.Inadditionto B.Otherthan C.Insteadof D.Inspiteof 13A.touched B.breathed C.felt D.tapped 14A.rushed B.jumped C.dropped D.floated 15A.explained B.whispered C.complained D.shouted 16A.anger B.desire C.manners D.dream 17A.heard B.followed C.shared D.refused 18A.mild B.weak C.powerful D.flexible 19A.resultin B.cometo C.consistof D.arisefrom 20A.dearer B.farther C.smaller D.closer
6分Differentcountrieshavedifferentcustomsespeciallyintablemanners.Somedininghabitsmaybeconsideredcivilizedinonecountrybutrudeinanother.Herearesomeinterestingfactsaboutsomecountries. France WheninFrancesplittingthebillAAwithfellowdinersshouldbeavoidedwhenpossible.You'reexpectedtooffertopaytheentirebillorsomeoneelseisexpectedtodg.so.OfcourseaccordingtoFrenchTodaytherearesomecasesWheresplittingthebillisOKlikewhendiningoutwithalargegroupofpeopleorwithcoworkers. Columbia Ifyou'reusedtocleaningyourplateyoumightwanttoconsidernotdoingsowhendininginColombiaIt'sconsideredrudetoleaveanemptyplatebecauseit'sasifyou'retellingyourhostthatheorshedidn'tgiveyouenoughfood. Australia InAustraliapeopletypicallyprefernottodiscussbusinessmattersoveramealaccordingtoEtiquetteScholarOfcourseitdependsonthepersonorgroupyou'rewithbutyoushouldpayattentiontoanycuesfromyourfellowdiningcompanionsforgoodmeasure. Kazakhstan InAmericait'sprettytypicaltogetannoyedwhenyourbaristadoesn'tfillyourcupalltheup.ButinKazakhstanitactuallyleaveyousatisfiedsinceitisagoodsign.AccordingtoEveryCulturehalf﹣filledcupsaremeanttokeepyourteawarmsinceyourhostwillcontinuouslyfillyourcupasawaytokeeptheinteractiongoingIfyourhostorserverweretofillyourcupwithteahoweveritisasignthattheymightwantyoutoleaveaccordingtoCommisceoGlobal. 1InFrancewithwhomissplittingthebillOKnowwhendining? A.yourchildren B.yoursweethearts C.yourcoworkers D.yourparents 2Inwhichcountryyouhadbetterleavesomefoodontheplate? A.France B.Columbia C.Australia D.Kazakhstan 3InKazakhstanifthehostfillsyourcupwithteaitmeansthat. A.youshouldleave B.youlikethetea C.youarethirsty D.theteatastesgood
15分Scotlandisauniqueplacewithlonghistorywhereyoucanfindnoble1palaceandcastles.Ithassomeof2mostbeautifulcitiesinEuropelivingwitnessofaproudandexcellentpast. 3discoverthetruesoulofScotlandtodaywehavetogotowardsthenorthernregionstotheGrampianMountainsItwasdifficulttofarmbuttheScotsdefeatedtheenvironmentwithstrongarms.Thehistoryofthisancientstruggleanditspeople'sancientloveforthehardlandare4apparentshownintheAngusFolkMuseum.Youcangetafeelofthetypicalruralatmosphereofpasttimesfromthedailyman﹣madeobjects5displayhere. FromcoastalAberdeen6theinsideoftheGrampianMountainsthererunstheCastleTrailaroadwithmanyfortresses要塞7arewitnessesof8continuefightsagainsttheruleofEnglandinScottishhistory. Another9attracthereisalegendarymonstertheLochNessMonster.Isthismonsterwhich10collectagood3000sightingsoverthelast50yearsrealorimaginary?Tomeetthecuriosityaboutitapriceof500000poundshasbeenputonthemonster'shead.
空气的成分中体积分数约占21%的是
下列物质中不需密封保存的是
15分假如你是李华最近刚到美国一所大学求学在学习生活上遇到了问题想向导师Mr.Brown求助.请你写封邮件内容包括 1.问题描述2.请求帮助3.预约时间. 注意1.词数80左右2.可以适当增加细节以使行文连贯.
下列物质中含有氧分子的是
25分2019年元宵节LanternFestival故宫首次开放衣场旅游盛况空前假定你是李华你的朋友Jack参观了元宵故宫灯会lanternshow.现你校文学社LiteratureClub要征集役游故宫灯会经历的稿件请你写一封电子邮件邀请Jack投稿内容包括 1.稿件主题夜游故言灯会经历和感受 2.截止日期2019年3月31日 3.投稿方式邮箱20190678@qq.com 注意1.词数100左右 2.可适当增加细节以使行文连贯. DearJack Yours LiHua
8分Ifyouaskmostpeoplewhatwatertasteslikethey'llprobablytellyouthatwaterhasnotasteandtheymaygiveyouafunnylook.Butifyouwereafruitflyaskinganotherfruitflythatquestionmighthaveadifferentanswer. Toafruitflywaterhasataste.Scientistswanttoknowhowthefruitflyknowswaterbecausethisinformationmayhelpinlearninghowotheranimalsmanagetousewaterintherightway.Waterisveryimportanttolifebuttoomuchortoolittlecanbedeadlytoalivingcreature.Sobyunderstandinghowthefruitflytasteswaterresearchersmaylearnmoreaboutotherlivingthings. AccordingtothenewstudyaproteincalledPPK28makesitpossibleforaflytotastewater.Proteinsbuildcellsandtissuesfightdiseaseandcarrymessagesbetweencells.It'snotsurprisingthataproteinisresponsibleforthefruitfly'sabilitytotastewater. ThePPK28proteinispartofalargerfamilyofsimilarproteins.Oneoftheserelatedproteinsisusedbymammalsincludinghumanstotastesalt.Scientistshavenotfoundaproteinthatenableshumanstotastewater.IntheexperimentCameronandhisteamcomparednormalfruitflieswithfruitflieswhosetastecellshadhadbeendisabled.ThefruitfliesweregivenaspecialchemicalthatwouldglowwhentheflyusedthePPK28protein.Thenthescientistsledthefliestowater.WhenthenormalfliestastedthewaterthePPK28proteinlitup﹣showingthatitwasinuse.Thefruitflyinparticularissointerestingthatsomescientistsarehardatworkcreatingacompletemapofthefruitflybrain.Thismapwillshowallofafly'sneuronsandhelpscientistsunderstandhowtheneuronsworktogether. 1Howdomostpeoplefeelwhenaskedthetasteofwater? A.Disappointed B.Frightened. C.Amused D.Disgusted. 2Whydoscientistswanttounderstandhowthefruitflyknowswater? A.Todecreasethenumberofthefruitfly. B.Toknowmoreaboutothercreatures. C.Tomanagetousewatercorrectly. D.Todescribethetasteofwater. 3WhatdoweknowaboutthePPk28protein? A.Itcanmakehumanstastesalt. B.Itenablesthefruitflytotastewater. C.Thefruitflycan'tlivewithoutit. D.Thefruitflyusesittoavoidillnesses. 4Whatwillthescientistscontinuetoworkat? A.MakingthePPk28protein. B.Tellingmoreinformationaboutcells. C.Creatingmapsofhumanbrains. D.Studyingthefruitfly'sneuronsystems.
7.5分IntheU.S.stateofWashingtonaroadcalled^Interstate90^cutsthroughawildmountainousareatoreachthecityofSeattle.Forthearea'smanykindsofanimalsthebusyhighwaygreatlylimitstheirmovements.Crossing1﹣90﹣astheroadiscalled﹣isariskybutsometimesnecessaryact.Butsoonanimalswillhaveasaferchoiceforcrossingtheroad.Theywillbeabletogoaboveit. Tohelptheanimalsthestateisfinishingworkonitslargest﹣everwildlifebridge.The11﹣meter﹣tall20﹣meter﹣widestructurebeginsintheforest.Itformstwoarchesabovethehighwayoneforeachdirectionoftraffic.Workersareaddingfencingandplantstohelpguidetheanimalsacrossthebridge.Two﹣meter﹣thickwallswillhelpblocknoisefromvehiclesbelow. The1﹣90BridgeispartofagrowingnumberofwildlifecrossingsacrosstheUnitedStates.Somearefencessomeareoverlandbridgesandsomeareunderpasses.Theyallaimtokeepdriversandanimalsawayfromeachother.Collisionsbetweenanimalsanddriversarerarelydeadlytopeople.Buttheyareoftendeadlytowildlife.InCanada'sBanffNationalParkstudieshavefoundthatwildlifecrossingsreducethearea'sanimal﹣drivercollisionsby80percent. Mostofthewildlifebridgesareinwesternstates.Butexpertshavenotedmanyotherareasthathaveaneedforsuchpaths.JenWatkinswhoseorganizationhashelpedcampaignforanimalcrossingssaysftindformorecrossingsisthenumber﹣onebarrier. PattyGarvey﹣DardaoftheU.S.ForestServicehasworkedonthe1﹣90crossingfromthestartoftheproject.Shesaysthe﹩6﹣millionbridgewillonedaypayforitselfbecausethehighwaywillnothavetobefullyorpartlyclosedeachtimealargeanimalisstruck.ShesaidIfyoushutdownInterstate90youshutdowninterstatecommerce. 1WhatisthepurposeofbuildingthebridgeoverInterstate90? A.Toreducehumandeathsincrashwithwildlife. B.Topreventwildlifefrombeingstruckbyvehicles. C.Toarousepublicawarenessofwildlifeprotection. D.Toprovideasaferchoicetocrosstheriskyroad﹣ 2AccordingtoJenWatkinswhatisthebiggestchallengeincrossingconstruction? A.Findingwaystohelpguideanimalsacrossthebridge. B.Collectingmoneytobuildmorewildlifecrossings. C.Locatingareastoconstructappropriatecrossings. D.Encouragedriverstoobeytheregulationsoftraffic. 3WhatdotheunderlinedwordsinParagraph5imply? A.Thebridgewillprovetobewellworththehighprice. B.Expenseforbuildingsuchbridgeswillbereduced. C.Thebridgewillgreatlypromotetradeandcommerce. D.Livessavedthroughthebridgearedefinitelybeyondprice.
30分Cruz11andAnthony10couldn'tagreewerethebirdsoutontheiceducksorgeese?Therewasonlyonewaytofindout.Soona1Januaryeveninglastyearthetwofriends2ontothefrozenpondneartheirhomesinFrankfortIllinoistogeta3look.Firsttheythrewarockontotheiceto4itthentheysteppedonit.5theicewouldholdtheirweightAnthonytookafewstepsthen…FOOMP.Hecrashed6theseeminglyfrozensurface.TherewasnosoundnocrackhesaidIjustfellthrough7. Cruzrushedtohelphis8friend.FOOMP﹣thepond9himtoo.Theboyswereuptotheirnecksinicywaterandquicklylosing10intheirlimbs.Anychanceoftheirfreeingthemselveswas11.Cruzwassurehewasgoingtodie.Anthony'ssisterhadseenitandstartedscreamingforhelp. JohnLavinaneighbor12nearbyheardherandquicklypulledover.Seeingtheboyshegrabbedanearbybuoy救生圈withonehandkickedoffhis13andranintotheicywaterhittinghiswaythroughtheicewithhisfree14.EventuallyLavin15hiswaytoCruzandAnthonyandpulledthembacktoland.Theyweretakentothe16wheredoctorsdiscoveredthattheirfive﹣minutestayinthewaterhad17theirbodytemperaturenearlytendegrees. 18theboyshavefullyrecoveredthankstotheir19neighbor.JusttothinksaysCruz20hewasn'tthereIcouldhavedied. 1A.warm B.chilly C.rainy D.windy 2A.toured B.rushed C.ventured D.wandered 3A.casual B.actual C.better D.deeper 4A.test B.break C.hit D.see 5A.Bothered B.Persuaded C.Concerned D.Convinced 6A.through B.onto C.in D.across 7A.slowly B.apparently C.instantly D.gradually 8A.discouraged B.panicked C.frustrated D.confused 9A.drowned B.drew C.embraced D.swallowed 10A.balance B.feeling C.faith D.heart 11A.givingaway B.slippingaway C.slippingout D.givingout 12A.driving B.passing C.coming D.walking 13A.bags B.gloves C.shoes D.clothes 14A.fist B.leg C.arm D.finger 15A.felt B.broke C.swam D.made 16A.shelter B.home C.school D.hospital 17A.lowered B.raised C.lessened D.changed 18A.Unexpectedly B.Fortunately C.Naturally D.Immediately 19A.strong B.considerate C.fearless D.friendly 20A.unless B.until C.when D.if
干冰常用于人工降雨利用了干冰的性质.
化学晚会上小明表演了一个小魔术﹣﹣“矿泉水”变成“牛奶”“雪碧”和“红酒”.回答下列问题 1“矿泉水”实际是石灰水加入液体A后出现白色浑浊形似牛奶该过程发生反应的化学方程式为. 2“牛奶”中加入B有大量气泡产生变成雪碧则B物质是该过程发生的化学反应最多有个. 3C是一种紫色的溶液滴入“雪碧”中变为红色则雪碧的组成是.
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