- 問題詳情:如圖,四稜錐P-ABCD中,側面PAD是邊長為2的等邊三角形且垂直於底,,,是的中點。(1)*:直線平面;(2)點在稜上,且直線與底面所成角為,求二面角的餘弦值。【回答】【解析】試題分析:(1)取的中點,連結,,由題意*得∥,利用線面平行的判斷定理即可*得結論;(2)建立空間直角座標系,求得半平面的法向量...
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- 問題詳情:在四稜錐P-ABCD中,AD∥BC,,G是PB的中點,△PAD是等邊三角形,平面PAD⊥平面ABCD.(Ⅰ)求*:CD⊥平面GAC;(Ⅱ)求二面角P-AG-C的正弦值.【回答】知識點:點直線平面之間的位置題型:解答題...
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- 1、scratchpadmemory2、scratchpadregister3、DoyouhaveascratchpadIcanwriteon?4、Theinventionrelatestoamulticolorscratchpad,acollatingmethodthereofandamulticolorscratchpadcollatingmachine....
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- LateMondayafternoon,readingtheobscureandintricatemarkings,theyidentifiedalaunchingpad.Thecenterpiecewasanornatemodelrocketonagreenfaunalaunchingpad.UponreturningtoEngland,heemployedthefavorablemediaattentionasalaunchingpadforhisforayintopolitics.Usin...
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- 問題詳情:小明喜歡利用pad聽歌,根據聲音的(選填“音調”、“響度”或“音*”)就判斷出是哪位歌手;音量太大會使耳膜受損,説明聲能傳遞 (“信息”或“能量”),為此需要減小聲音的 (“音調”、“響度”或“音*”).【回答】【分析】聲音不但能傳遞信息,還能夠傳遞能量;聲音的三個特徵分...
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- 問題詳情:在四稜錐△PAD為正三角形,且平面PAD⊥平面ABCD.(1)求二面角P-EC-D的餘弦值;(2)線段PC上是否存在一點M,使得異面直線DM和PE所成的角的餘弦值為若存在,指出點M的位置;若不存在,請説明理由.【回答】知識點:點直線平面之間的位置題型:解答題...
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- Thespaceshipwillliftofffromthelaunchingpadat7a.m.Thecenterpiecewasanornatemodelrocketonagreenfaunalaunchingpad.Usingthegrantfundingasalaunchingpad,projectsoftengoontoscaleuporreplicateelsewhere,winningprestigiousawardswithinthesphereofsocialentrepren...
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- Iusegroundedmousepad,IuseuniversalMATS,Iwalkbarefoot.AdvertisingGifts:advertisingmousepad,personalizedclothslippers,coasters,barMATS,wallpicture,flags,advertisingcapandsoon.Ifyou'realwaysjottingthingsdown,afreshnotepadanduncappedpenshouldbenexttoyou...
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- 問題詳情:如圖,平面PAD⊥平面ABCD,四邊形ABCD為正方形,∠PAD=90°,且PA=AD=2,E,F分別是線段PA,CD的中點,則異面直線EF與BD所成角的餘弦值為.【回答】 知識點:三角函數題型:填空題...
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- 問題詳情:如圖,在四稜錐P-ABCD中,側面PAD為正三角形,底面ABCD為正方形,側面PAD⊥底面ABCD,M為底面ABCD內的一個動點,且滿足MP=MC,則點M在正方形ABCD內的軌跡為下圖中的【回答】A知識點:空間幾何體題型:選擇題...
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- Hoptothatlilypadinthesky,oldfriend.AgreenfrogsitsatopalargelilypadinthewatersofAtchafalayaDelta.WhenCharleysawWandahejumpedontoalilypad."Hi,"hecried.Hewasahandsomeprincebutawetone.Thelilypadhadcollapsedunderhisweightanddumpedhimintothewater.Oilspil...
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- 1、Hewrotedownatelephonenumberonamemopad.2、Inthedream,hereachedfortheblueballpointpeninhisbreastpockettojotsomethingdownonhismemopad.3、Thephonehasanintegratedquicknotefunction,whichletsyoupullupasticky-sizememopadfromanypageonthedevice.4、Forexampl...
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- Helostallhismoneyandhadtopadithome.Ididn'tbuysilkthread.Letherpaditfirst.Embroideryisthesameasyours.Howmuchisthemanualcostofembroidery?...
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- Startbynotbuyingyourselfasketchpad.Comparedtothephonologicalloopandthevisuospatialsketchpad,thecentralexecutivemayhaveakeyroleinchildren'sarithmeticcognition.Comparedtothephonologicalloopandthevisuospatialsketchpad,thecentralexecutivemayhaveakeyrole...
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- Shesmasheditusingthephone'sspecial'SWYPE'keypad,whichenablesuserstoinputtextwithouttheirfingertipleavingthescreen.Inwordprocessing,aseparatesetofkeysnumbered0through9onawordprocessor'skeyboardthatallowseasyentryofnumbers,aligningthemautomatically...
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- 問題詳情:如圖,在四稜錐P﹣ABCD中,底面ABCD是邊長為2的正方形,側面PAD⊥底面ABCD,且PA=PD=AD,E、F分別為PC、BD的中點.(Ⅰ)求*:EF∥平面PAD;(Ⅱ)求*:面PAB⊥平面PDC;(Ⅲ)在線段AB上是否存在點G,使得二面角C﹣PD﹣G的餘弦值為?説明理由.【回答】【考點】平面與平面垂直的判定;直線與平面平行的判定;二...
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- 問題詳情:如圖,四稜錐P-ABCD中,側面PAD為等比三角形且垂直於底面ABCD,E是PD的中點.(1)*:直線平面PAB(2)點M在稜PC上,且直線BM與底面ABCD所成鋭角為,求二面角M-AB-D的餘弦值 【回答】【解析】(1)令中點為,連結,,.∵,為,中點,∴為的中位線,∴.又∵,∴.又∵,∴,∴.∴四邊形為平行四邊形,∴.又∵,∴(2)以中點...
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- 問題詳情:如圖,在四稜錐PABCD中,平面PAD⊥平面ABCD,AB=AD,∠BAD=60°,E,F分別是AP,AD的中點.求*:(1)直線EF∥平面PCD;(2)平面BEF⊥平面PAD.【回答】*略知識點:點直線平面之間的位置題型:解答題...
- 6826
- Inthisarticle,bondingpaddesign,stencildesignandassemblyprocessofQFNdevicewillbeintroducedindetail.Thebondingpadofthecircuitboardisprovidedwiththegap,thegapandthepositioningholearespacedbycertainintervaltoavoidtinleaking....
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- Scrubeachopticalsurfacewithagauzepadsoakedinacetone.Ihadtopayrushshippingformybirthkit—allthesterilizedgauzepads,alcoholswabs,glovesandgoopthemidwifeneedsatthebirth.Firstaidkit.Itshouldhavelatexgloves,gauzepads,thermometer,sterilebandages,band-aids,...
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- 1、Theminutestickedby.Bobscribbledawayonthepad.2、Willbeflatonthecorrugatedboardflatonthepad.3、Giventhefactthatthetargetsiteis580kilometersfromShuangchengzi,itispossiblethataDF-15CtestseriesresultedintheHEimpactsonthepad....
- 20425
- 問題詳情:如圖,在四稜錐P-ABCD中,側面PAD為正三角形,底面ABCD為正方形,側面PAD⊥底面ABCD,M為底面ABCD內的一個動點,且滿足MP=MC,則點M在正方形ABCD內的軌跡為( ) A. B. C. ...
- 21303
- telephonenumBerswrittenonapadShewroteonapadofpaper.NexttoPaulsen,NimGoldmandoodledthoughtfullyonapad.Heputonapadofgauzeandastripofadhesivetapeoverthewound.Mobilehomeortrailersmaybeonapadwhichyourentinamobilehomepark.Thechipsstorepersonaldatathatcanbe...
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- 問題詳情:已知定點A(3,4),點P為拋物線y2=4x上一動點,點P到直線x=-1距離為d,則|PA|+d的最小值為( )A. B.2 C. D.【回答】A知識點:圓錐曲線與方程題型:選擇題...
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- Then,onesteamingAugustnightbetweenmortarattacks,thechaplainaskedforavolunteertodrivehimtothehelicopterpadthefollowingweekend.ThereisahelicopterpadrightinfrontofthesideofthePentagon.Thewingtouchedthere,thentheplanecartwheeledintothebuilding.OntheHesse...
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