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發表於:2019-10-25
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( ) ...
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發表於:2018-07-26
Whentypingonakeyboard,shouldbethewristpad,avoidwiththeforearmraised.Ensurethattheactivityisageappropriateandprovideprotectiveequipmentsuchashelmets,wristpads,andkneepads....
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發表於:2019-12-10
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...
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發表於:2021-02-04
問題詳情:如圖,四稜錐P-ABCD中,底面ABCD為矩形,側面PAD為正三角形,且平面PAD⊥平面ABCD,E為PD中點,AD=2.(1)求*:平面AEC⊥平面PCD;(2)若二面角A-PC-E的平面角大小θ滿足,求四稜錐P-ABCD的體積. ...
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發表於:2019-09-04
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....
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發表於:2017-07-17
Fixedthattheplayercharacterwouldmoveincorrectlyonthelandingpadifthepadwasflooded.TheritziesthotelinMuscatoffersahelicopterlandingpadoutback.Ifthethoughtofpublictoiletwate...
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發表於:2018-01-09
Then,onesteamingAugustnightbetweenmortarattacks,thechaplainaskedforavolunteertodrivehimtothehelicopterpadthefollowingweekend.Thereisahelicopterpadrightinfrontofthesideoft...
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發表於:2017-08-24
Inthisarticle,bondingpaddesign,stencildesignandassemblyprocessofQFNdevicewillbeintroducedindetail.Thebondingpadofthecircuitboardisprovidedwiththegap,thegapandthepositioni...
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發表於:2020-06-28
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...
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發表於:2021-06-03
問題詳情:已知四稜錐P-ABCD的頂點都在球O上,底面ABCD是矩形,平面PAD⊥平面ABCD,△PAD為正三角形,AB=2AD=4,則球O的表面積為()A. B. ...
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發表於:2017-07-07
fixingofshoulderpadThepadisimpregnatedwithinsecticide.Neverpadoutyouressaywithirrelevantdetails.Startbynotbuyingyourselfasketchpad.Sheseesthestamppadonmysweater.Amongthos...
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發表於:2022-08-10
CleaningProductSeriesisincludingspecialscouringpad,spongescouringpadandmultifunctionalscrubbrush.Roundsupplyofnylonabrasivepolishingabrasives,includinggrindingwheels,wing...
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發表於:2018-11-18
Helostallhismoneyandhadtopadithome.Ididn'tbuysilkthread.Letherpaditfirst.Embroideryisthesameasyours.Howmuchisthemanualcostofembroidery?...
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發表於:2020-03-16
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,,...
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發表於:2022-04-19
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...
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發表於:2018-05-13
Asanitarybreastpadrelatestothetechnicalfieldofwomanhealth-carearticles,inparticulartoasanitarypadusedforkeepingthecircumferenceandclothesdryforwomeninlactationperiod.Fore...
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發表於:2022-04-18
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...
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發表於:2020-04-30
問題詳情: 如圖,在四稜錐P-ABCD中,底面ABCD為平行四邊形,己知AP=AC=AB=2,∠PAD=∠DAC=60°.(1)求*:AD丄PC;(2)若平面PAD丄平面ABCD,求二面角C-PD-A的餘弦值.【回答】知識點:點直線平面之間的...
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發表於:2016-10-17
Thereportersreportedthatthelaunchpadwasonfireafterthelaunch.Themilitaryhasnotbeenabletodeterminetheexactlocationofthelaunchpad.Therocketexplodedonthelaunchpad,burningaliv...
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發表於:2020-10-19
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”、“...
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發表於:2018-05-17
Thespaceshipwillliftofffromthelaunchingpadat7a.m.Thecenterpiecewasanornatemodelrocketonagreenfaunalaunchingpad.Usingthegrantfundingasalaunchingpad,projectsoftengoontoscal...
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發表於:2022-03-24
telephonenumBerswrittenonapadShewroteonapadofpaper.NexttoPaulsen,NimGoldmandoodledthoughtfullyonapad.Heputonapadofgauzeandastripofadhesivetapeoverthewound.Mobilehomeortra...
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發表於:2021-10-03
問題詳情:如圖,在四稜錐P-ABCD中,底面ABCD為正方形,平面PAD⊥平面ABCD,點M在線段PB上,PD//平面MAC,PA=PD=,AB=4.(I)求*:M為PB的中點;(II)求二面角B-PD-A的大小;(III)求直線MC與平面BDP所成角的正弦值.【回...
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發表於:2020-09-14
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】(1)見解析;(2)【詳解】試題分析:(1)取的中點,連...
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發表於:2021-05-09
問題詳情:如圖,在四稜錐P-ABCD中,底面ABCD為菱形,△PAD為正三角形,平面PAD上平面ABCD,E,F分別是AD,CD的中點. (I)*:BD⊥平面PEF; (Ⅱ)若∠BAD=60°,求二面角B-PD-A的餘弦值.【回答】知識點:...