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如图，四边形ABCD与四边形EFGH位似为点O，且＝，这＝ ．
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以四边形ABCD的边ABBCCDDA为斜边分别向外侧作等腰直角三角形直角顶点分别为EFGH顺次连接这
如图四边形ABCD与四边形AEFG是位似图形且AC∶AF＝2∶3则下列结论不正确的是
四边形ABCD与四边形AEFG是相似图形
AD与AE的比是2∶3
四边形ABCD与四边形AEFG的周长比为2∶3
四边形ABCD与四边形AEFG的面积比为4∶9
在空间四边形ABCD中E.F.分别为ABAD上的点且AE∶EB＝AF∶FD＝1∶4又H.G.分别为B
BD∥平面EFG，且四边形EFGH是平行四边形
EF∥平面BCD，且四边形EFGH是梯形
HG∥平面ABD，且四边形EFGH是平行四边形
EH∥平面ADC，且四边形EFGH是梯形
观察控究完成证明和填空.如图四边形ABCD中点E.F.G.H.分别是边ABBCCDDA的中点顺次连接
我们给出如下定义顺次连接任意一个四边形各边中点所得的四边形叫中点四边形.1如图1四边形ABCD中点E
我们给出如下定义顺次连接任意一个四边形各边中点所得的四边形叫中点四边形.1如图1四边形ABCD中点E
如图E.F.G.H.分别为四边形ABCD四边之中点.1求证四边形EFGH为平行四边形2当ACBD满足
观察控究完成证明和填空.如图四边形ABCD中点E.F.G.H.分别是边ABBCCDDA的中点顺次连接
观察控究完成证明和填空.如图四边形ABCD中点E.F.G.H.分别是边ABBCCDDA的中点顺次连接
以四边形ABCD的边ABBCCDDA为斜边分别向外侧作等腰直角三角形直角顶点分别为E.F.G.H.顺
如图所示在空间四边形ABCD中E.F.分别为边ABAD上的点且AE∶EB＝AF∶FD＝1∶4又H.G
BD∥平面EFGH，且四边形EFGH 是矩形
EF∥平面BCD，且四边形EFGH是梯形
HG∥平面ABD，且四边形EFGH是菱形
EH∥平面ADC，且四边形EFGH是平行四边形
在空间四边形ABCD中E.F.分别为ABAD上的点且AE∶EB＝AF∶FD＝1∶4又H.G.分别为B
BD∥平面EFG，且四边形EFGH是平行四边形
EF∥平面BCD，且四边形EFGH是梯形
HG∥平面ABD，且四边形EFGH是平行四边形
EH∥平面ADC，且四边形EFGH是梯形
观察控究完成证明和填空.如图四边形ABCD中点E.F.G.H.分别是边ABBCCDDA的中点顺次连接
观察探究完成说明和填空.如图①在四边形ABCD中点E.F.G.H.分别是边ABBCCDDA的中点顺次
如果四边形ABCD的位似图形为四边形A'B'C'D'且O为位似中心那么下列说法中正确的是
O一定在四边形ABCD外
O不能在四边形ABCD上
若OA：OA'=1：2，则可得到放大两倍的位似图形
O在四边形ABCD外时，只能得到放大的位似图形
如图已知四边形ABCD和点O画四边形EFGH使四边形EFGH和四边形ABCD关于点O成中心对称．
如图在四边形ABCD中对角线ACBD相交于点O.且AC⊥BD点E.F.G.H.分别是ABBCCDDA
如图点O.是四边形ABCD和四边形EFGH的位似中心已知AE＝2EO＝1则四边形ABCD与四边形EF
如图点E.F.G.H.分别是四边形ABCD边AB.BC.CD.DA的中点.则下列说法①若AC=BD则
1
2
3
4
如图四边形ABCD中E.F.G.日分别为各边的中点顺次连结E.F.G.H.把四边形EFGH称为中点四
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已知函数fx＝|2x+m﹣1|+|2x﹣3|． 1当m＝2时求不等式fx≤6的解集 2若fx≤|2x﹣6|的解集包含区求m的取值范围．
Ifyouwearglasseschancesareyouaresmarter.ResearchpublishedinthefamousBritishjournalNatureCommunicationshasfoundthatpeoplewhodisplayedhigherlevelsofintelligencewerealmost30percentmorelikelytowearglasses. Thescientistsstudiedthegenesofthousandsofpeoplebetweentheagesof16and102.Thestudyshowedintelligencecanbeconnectedtophysicalcharacteristics.Onecharacteristicwaseyesight.In3outof10peoplewhoweremoreintelligenttherewasahigherchancetheyneedglasses.Scientistsalsosaidbeingsmarterhasotherbenefits.Itisconnectedtobetterhealth. Itisimportanttoremembertheseareconnectionswhicharenotprovencauses.Scientistscallthiscorrelation.Justbecausesomethingisconnectedtosomethingelsedoesnotmeanoneofthosethingscausedtheother.Andit'sworthnotingthatwhatconstitutes构成intelligenceissubjectiveandcanbedifficultifnotimpossibletomeasure. Forgetgenesthough.Plentyofproofshowswearingglassesmakespeoplethinkyouaremoreintelligentevenifyoudonotneedglasses.Anumberofstudieshavefoundpeoplewhowearglassesareseenassmarterhard﹣workingandhonest.Manylawyersusethisideatohelpwintheircases.LawyerHarveySlovisexplainedthis.Glassessoftentheirappearancehesaid.Sometimestherehasbeenahugeamountofproofshowingthatpeoplehewasdefendingbrokethelaw.Hehadthemwearglassesandtheyweren'tfoundguilty. GlassesarealsousedtoshowsomeoneisintelligentinmoviesandonTVIdeasaboutpeoplewhowearglasseshavebeguntoshift.Peoplewhodonotneedglassessometimeswearthemforfashiononly.Theywanttolookworldlyorcool.Butnoteveryoneisimpressedbythisideathough.GQmagazinesaidpeoplewhowearglassesforfashionaretryingtoohardtolooksmartandhip时髦的.Howeverthathasn'tstoppedmanycelebrities名人fromhappilywearingglasseseveniftheydonotneedthem.JustenBieberisjustonehigh﹣profilefanoffashionglasses. 1Whatdoesthenewstudyshow? A.Peoplewearingglassesaresmarter. B.Peoplewearingglassesarehealthier. C.Wearingglassescanmakepeoplecleverer. D.WearingglassesisassociatedwithhigherIQ. 2WhatdoestheunderlinedwordcorrelationinParagraph3mean? A.Shift. B.Link. C.Proof. D.Consequence. 3Whydosomelawyersasktheirclientstowearglassesincourt? A.Becauseitcancreateamoralimage. B.Becauseitcanmisleadthewitnesses. C.Becauseitcanhighlightclients'qualities. D.Becauseitcanprovetheclients'innocence. 4Whatisthegeneralattitudetothosewhowearglassesforfashion? A.Positive. B.Negative. C.Mixed. D.Indifferent.
ForalongtimeIthoughtapresentandagiftwerenodifferent.Igrewupinahouseholdwherepresents1specialoccasionssaytherewerealwayspresentsforChristmasandourbirthdays. SowhenImarriedGarywhodidnotgivepresentsona2basisIhadtomakeanadjustment.Garydidnotwhollyavoidgift﹣givingthough.3noticinghowmanyhoursIspendonthe4hebroughthomeashoulderpad垫肩forthetelephonereceiver.Butmostlyhe5holidaysletaloneshopforearringsto6tomeshowinghisaffection. Itriedtochangehim7.IboughtbooksforhisbirthdaysandknittedhimhatsandsweatersforChristmas.8IbegantotellhimwhatIwantedgiving9instructionsbutgotnowhere. Lastyearwhenthesnowstorm10ourtownandhewasonbusinessIusedhispresent﹣roadscraper铲土机to11bothourdriveandourneighbor'sthinkinghow12earringswouldhavebeen.GaryhadwiselychosennotthethingI13butthethingthatheknewIwouldneed. I14begantounderstandthedifferencebetweenapresentandagift.Apresentisjustathing.Butagiftisbroaderandoftencannotbe15.Itisasmallactofkindnessthe16tobendtoanother'sneedsthesacrificeoftimeandeffort.17isagift.Anyexpressionofitfreelygivenisan18fromtheheartthatisimmeasurablybetterthanapresent. MyinsistenceonpresentsmusthaveseemedtoGaryalackof19.forthegiftshehadbeengivingallalongbutheneverstoppedgivingthem. GarywillbehomethisChristmasbutIdon't20apresent.Ialreadyhavethegreatestgift. 1A.marked B.involved C.expressed D.displayed 2A.daily B.rare C.temporary D.regular 3A.Therefore B.Once C.Then D.Besides 4A.gardening B.cooking C.telephone D.Internet 5A.missed B.hated C.abandoned D.ignored 6A.serve B.refer C.present D.relate 7A.bytradition B.byforce C.byexample D.bychance 8A.Yet B.Even C.Thus D.Still 9A.useful B.simple C.specific D.interesting 10A.struck B.disappeared C.melted D.passed 11A.clearup B.tearup C.buildup D.speedup 12A.priceless B.useless C.weightless D.colorless 13A.valued B.prepared C.preserved D.desired 14A.eventually B.definitely C.simply D.totally 15A.obtained B.discovered C.measured D.observed 16A.happiness B.willingness C.wisdom D.freedom 17A.Love B.Passion C.Insistence D.Motivation 18A.sharing B.offering C.following D.experiencing 19A.desire B.concern C.preparation D.appreciation 20A.purchase B.order C.expect D.evaluate
过双曲线的右焦点F作垂直于x轴的直线交双曲线于AB两点若△OABO为坐标原点为等腰直角三角形则该双曲线的离心率为
曲线y＝x+1ex在点01处的切线方程为．
TopMusicFestivals Festivalseasonisjustkickingoffandthereisalottolookforwardtointheupcomingmonths. FireflyMusicFestival Manypeoplehaven'tthoughtofgoingtoDelawareforasummervacationbutmid﹣Juneisagreattimetoplanthistripifyoulovemusic.Headlinersforthisyear'sshowareTheWeekendMuseTwenty﹣OnePilotsChancetheRapperandBobDylan. Date:June15﹣182017 Location:DoverDelawareUSA MusicType:Rock Price:＄79﹣＄2499 RoskildeFestival ThisDenmarkmusicfestivalhasbeenalocaltraditionsince1971.Therewillbeninestagesforthisyear'seventstohostgroupsliketheFooFightersBlink182andTheLumineers.What'sinterestingaboutthisfestivalisthatinadditiontothebigheadlinersyoucanalsogettoknowup﹣and﹣comingregionalartistsfromDenmarkSwedenandNorway. Date:June24﹣July12017 Location:RoskildeDenmark MusicType:Rockemergingregionalartists Price:DKK995﹣DKK1995around＄144﹣＄289 SecretSolstice WithlongdarkandcoldwintersnobodycelebratessummerquitelikeIcelanders.ToseeforyourselfplanatriptoIcelandthisJunetocheckouttheSecretSolsticefestival.NotonlywillyouenjoyseeingbandslikeRadioheadandAfrikaBambaataabutyoucanalsoexperiencetheother﹣worldlylandscapesandgeothermal地热的springsnearbyaswell. Date:June15﹣182017 Location:ReykjavikIceland MusicType:EclecticIndie Price:€149﹣€1599around＄160﹣＄1725 MontrealJazzFestival AlljazzloversoweittothemselvestocheckouttheMontrealJazzFestivalatleastonceinalifetime.ThiseventbringstogethersomeofthebestnamesinjazzmusicaswellasdiverseR&Bfunk骤停打击乐andsoulartists. Date:June28﹣July82017 Location:MontrealQuebecCanada MusicType:JazzR&BSoulFunk Price:＄27.25﹣＄210.25 1Whatiscommontothemusicfestivalsmentionedinthetext? A.TheyareheldinEurope. B.Theirmusictypesarerockandhip﹣hop. C.Theyaregivenintheopenair. D.Theytakeplaceinsummer. 2WhatcanweinferaboutDelawarefromthetext? A.Itisthecityofmusic. B.Itisnotasummerdestination. C.ItisthehomeofBobDylan. D.Itisacityofhighexpense. 3WhatisthepurposeofIcelanderstoholdtheSecretSolsticefestival? A.Towelcomesummer. B.Tomemorizethepastwinter. C.Tocelebratethecomingofspring. D.Toadvisethelocalbeautifullandscapes.
WhenMr.WangaChinesecalligraphy书法masterandpainterinvitedmetohisstudioIgotextremely1delight.Whatatreat! Hisapartmentdoublesashisstudio2hecreatescalligraphyworksandpaintingsaswell.Thelivingroomhasalongdeskwithacollectionof3brushofvaryingsizestwobiginkpotsandapairofpaperweights. Mr.Wangshowedhislatestworkascroll卷轴oftheGreatWallatBadaling4winditswayalongthesteephillswhich5recognizeasaWorldHeritageSitebytheUnitedNationsin1987.Thebeautyoftheseven﹣meter﹣longscrollpaintingwasbeyond6describe. Hetoldmesomeonehadofferedalargeamountofmoneyforthepaintingbutherefused7partwithitashewantedtodonatetotheNationalMuseum. AfterthatMr.WanginvitedmetopracticecalligraphyanditwasthefirsttimethatIhad8trueexperiencedthebeautyoftheline.Itwasthen9InoticedMr.Wangappearedtohaveahealthybody.Iwonderedifpracticingcalligraphykepthimsofit.Whetherthatistrueonethingiscertain;asMr.Wangput10Onlydoonethinganddoitwell﹣﹣﹣that'sthesecrettosuccess
Earlierthismonthastudyshowedthatbeescanteachthemselvestoplayfootball.Theycanlearnbywatchingandratherthancopywhattheyhaveseenchangeittomakeitbetter.Beesalsohaveaclevertrickforhelpingtheirfriendsfindlunch.Newresearchshowsthatbeesleavesmellylittlefootprintsonflowersthathelpthemknowwhatflowerstheyandtheirfamilymembershaverecentlyvisited. ThediscoverywasmadebyscientistsfromUniversityofBristolwhoreportthesesmellyfootprintshelpbeesdistinguishbetweentheirownscent气味thescentofarelativeandthescentofastranger.Andbyusingthisabilitybeescanimprovetheirsuccessatfindinggoodsourcesofafoodandavoidflowersthathavealreadybeenvisitedandminedofnutrients. TheBristolteamperformedthreeseparateexperimentswithbumblebees大黄蜂inwhichtheywererepeatedlyexposedtorewardingandunrewardingflowersatthesametimethathadfootprintsfromdifferentbeesattachedtothem.Eachflowertypeeithercarriedscent﹣marksfrombumblebeesofdifferingrelatednessorwereunmarked.Themarkswereeitherthebee'sownmarkssistersfromtheirnestorstrangersfromanothernest. Thestudyshowsthatnotonlycanbumblebeestellthemarksoftheirownnestmatesfromstrangersbuttheycanalsodiscriminatebetweenthesmelloftheirownfootprintsandthoseoftheirnestmatesisterswhichcouldhelpthemtorememberwhichflowerstheyhavevisitedrecently.Butitdoesn'texplainhowtheyusethatinthewild.Theymaydetectthefootprintsoftheirfriendsandkeepmovingonsincethatflowermaybetappedout.Ortheymaysmellabitoffamiliarfootsmellanddiveinseeingitasamarkerthatnectar花蜜ispresent. 1WhatcanweinferaboutbeesinParagraph1? A.Theyaresmartlearners. B.Theyhavestrongfamilyties. C.Theyenjoysmellyfootprints. D.Theylikeplayingtricksonothers. 2WhatdoesthisabilityinParagraph2referto? A.Findinggoodsourcesoffood. B.Followingotherbees'footprints. C.Tellingthesmellsoffootprintsapart. D.Recognizingdifferenttypesofflowers. 3Whatcanwelearnfromthefindingsoftheexperiments? A.It'seasierforBumblebeestorecognizetheirfriends. B.It'sunclearhowbumblebeesusetheirabilityinthewild. C.Bumblebees'memorycanbesignificantlyimproved. D.Bumblebees'footprintscangivethemasenseofidentity. 4Whatisthemainideaofthetext? A.Differentflowersattractdifferentbees. B.Beeshaveanewtrickofsurvivinginthewild. C.Bumblebeesmaysmellfootprintstokeeptrackoffood. D.Bumblebeescangiveoffuniquescentstoattractothers.
FourTipsforHighSchoolGraduates Overthree﹣millionhighschoolstudentsaregraduatingthisspringintheUnitedStates.Manyofthemwillheadtouniversityinthefall.Thetransition过渡fromhighschooltocollegeisamajoroneandsuccessfuladjustmenttocollegehaslifelonginfluences. Maybeyouareabouttomakethistransitionyourselforhavechildrenwhoareabouttoleavethenest.1Ifyouknowsomeonewhoismakingthistransitionorknowparentsguidingtheirsoon﹣to﹣beadultkidsthroughthistimepleasetakeamomenttosharethiscollectionofresearch﹣basedtipswiththem. Beopentomakingnewfriendsassoonasyousetfootoncampus.Evenduringorientation迎新会!2Yoursuccessincollegedependsinpartonsurroundingyourselfwithotherswhocansupportyouandhelpyouhavefun. 3Successfuladjustmentisaboutreachingoutforhelpwhenyouneedit.Thismeanstryingtofindtheanswersonyourownfirstbutthencontactingthosewhocanhelpyouwhenyoucan't.Thatiswhattheyaretherefor! Leanonyourfamily.Familysupportcangiveyoucomfortwhenclassesgethardoryouarestressedaboutfinals.4Strongsupportfromfamilyislinkedtolowerlonelinessanddepressionduringthefirstyearofcollegeandhigheracademicadjustmentincludingmotivationandconcentration. Beconfident.Feelinganxietyaboutcommunicatingwithfellowsprofessorsandspeakingupinclassisassociatedwithloweradaptationduringthetransitiontocollege.Oneofthebestwaystoincreaseyourcommunicationconfidenceistopractice!5 A.Thislistisforyou. B.Themoreyouspeakupinclasstheeasieritbecomes. C.Don'tbeafraidtotalktoyourprofessorsorteachingassistants. D.Joiningclubsisalsolinkedtofeelingsofbelongingatcollege. E.Yourprofessorsandteachingassistantswanttoseeyousucceedintheirclasses. F.Almosteveryoneisinthesameboatasyouarehopingtomakefriendsquickly. G.Familymemberscangiveyouadviceandhelpyousolveproblemsifyouneedhelp.
TheCreatorofMiddleEarth JohnRonaldReuelTolkienbetterknownasJ.R.R.Tolkienwasbornin1892inSouthAfrica.Hisparentshadmovedtherelookingfor1betterjobforhisfather.Threeyears2latehismothertookhimonatriptoEnglandtovisitfamily. Whiletheywereawaytheyreceivedterriblenewsthathisfatherhaddied. 3growupwithoutafathermusthavebeendifficultforTolkien.Worsestillwhenhewasonlytwelveyearsoldhismotheralsopassedaway.Asachildhehadagreatpassionforlanguageandin1908hewenttoOxfordUniversity4studylanguagesandliterature.In1915hejoinedthearmyandfoughtinthebattleagainsttheGermans.Butsoonhebecametooilltofightandreturned5Englandthefollowingyear.Hedidn'thavea6satisfychildhoodhimselfsoaroundin1933storyofahobbit霍比特人hespentmuchtimetellinghischildrenfantasy7calledBilbo.Hefirstputitinwritingin19368turnedouttobeasurprisinghit. Thepublisheraskedhimtowriteanother.Hedidsoandin1948publishedTheLordoftheRingswhich9publishinthreevolumesbetween1954and1955. Tolkien10ageeighty﹣onediedin1973.
已知函数fx＝ex1﹣ax﹣x2． 1求fx的单调区间 2若x≥0fx≤1求实数a的取值范围．
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