![已知a，b，c分别是△ABC的三个内角A、B、C所对的边，A、B、C成等差数列．(1)若a＝1，b＝，求sin...]( "已知a，b，c分别是△ABC的三个内角A、B、C所对的边，A、B、C成等差数列．(1)若a＝1，b＝，求sin...")
- 问题详情：已知a，b，c分别是△ABC的三个内角A、B、C所对的边，A、B、C成等差数列．(1)若a＝1，b＝，求sinC；(2)若a，b，c成等差数列，求*△ABC是等边三角形．【回答】解(1)由A＋B＋C＝π，2B＝A＋C得B＝，由＝，得＝，得sinA＝，又0＜a＜b，∴A＝，∴C＝π－－＝.∴sinC＝1.(2)*由2b＝a＋c，得4b2＝a2＋2ac＋c2，又b2＝a2＋c2－ac，得4a2＋4c2－4ac＝a2＋2ac＋c2，得3(a－c)2＝0，∴a＝c，∴A＝C，又A＋C...
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![已知sin(α＋)＝－，α∈(0，π)．(1)求的值；(2)求cos(2α－)的值．]( "已知sin(α＋)＝－，α∈(0，π)．(1)求的值；(2)求cos(2α－)的值．")
- 问题详情：已知sin(α＋)＝－，α∈(0，π)．(1)求的值；(2)求cos(2α－)的值．【回答】知识点：三角恒等变换题型：解答题...
- 13808
![—WhichcountryistheStatueofLibertyin?—It'sin]( "—WhichcountryistheStatueofLibertyin?—It'sin")
- 问题详情：—WhichcountryistheStatueofLibertyin?—It'sin________.A.B.C.D.【回答】C知识点：其他题型：选择题...
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![若sin（125°－α）=,则sin（α＋55°）= ．]( "若sin（125°－α）=,则sin（α＋55°）= ．")
- 问题详情：若sin（125°－α）=,则sin（α＋55°）= ．【回答】．知识点：三角函数题型：填空题...
- 8039
![besetting sin造句怎么写]( "besetting sin造句怎么写")
- Lazinessismybesettingsin.Hisbesettingsinislaziness.Castingreflectionsonothersisherbesettingsin.Dickwasafineperson,apartfromhisbesettingsin-hedranktoomuch....
- 27371
![original sin造句怎么写]( "original sin造句怎么写")
- 1、Hewaspleasanterthanoriginalsin.2、Butwhatistheoriginalsin?3、Mansevilnature,originalsinanddegeneration;4、asincommittedofyourownfreewill(ascontrastedwithoriginalsin).5、Theoriginalsinofbusinessschoolsisboosterism.6、theRomanCatholicdoctrinethatthe...
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![_____hespeakssoftlyisnoproofthatheiskind. A. Sin...]( "_____hespeakssoftlyisnoproofthatheiskind. A. Sin...")
- 问题详情：_____hespeakssoftlyisnoproofthatheiskind. A. Since B. As C. ThatD. Because【回答】C知识点：相似相近词比较题型：选择题...
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![已知cos（α﹣）=﹣，sin（﹣β）=，且0＜β＜＜α＜π，则sin= ．]( "已知cos（α﹣）=﹣，sin（﹣β）=，且0＜β＜＜α＜π，则sin= ．")
- 问题详情：已知cos（α﹣）=﹣，sin（﹣β）=，且0＜β＜＜α＜π，则sin=．【回答】．【考点】三角函数的化简求值．【分析】利用同角三角函数的基本关系求得sin（α﹣）和cos（﹣β）的值，再利用两角差的正弦公式求得sin的值．【解答】解：∵cos（α﹣）=﹣，sin（﹣β）=，且0＜β＜＜α＜π，∴α﹣∈（，π），sin（α﹣）==；﹣β∈（0，），cos（﹣β）==．则sin=sin[（α﹣）﹣（﹣β）]=sin（α﹣）cos（﹣β）﹣cos（...
- 10653
![---HaveyouknownDr.Jacksonforalongtime? ---Yes,sin...]( "---HaveyouknownDr.Jacksonforalongtime? ---Yes,sin...")
- 问题详情：---HaveyouknownDr.Jacksonforalongtime? ---Yes,sinceshe theChineseSociety. A.hasjoined B.joins C.hadjoined D.joined【回答】D知识点：...
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![--WhichcountryistheOperaHousein? --It'sin]( "--WhichcountryistheOperaHousein? --It'sin")
- 问题详情：--WhichcountryistheOperaHousein? --It'sin_______. 【回答】D知识点：其他题型：选择题...
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![若sin=,则sin()=( )A. B. C. D.]( "若sin=,则sin()=( )A. B. C. D.")
- 问题详情：若sin=,则sin()=( )A. B. C. D. 【回答】A知识点：三角函数题型：选择题...
- 13183
![若sin(π-α)=-且α∈,则sin=( )A.- B.- C. ...]( "若sin(π-α)=-且α∈,则sin=( )A.- B.- C. ...")
- 问题详情：若sin(π-α)=-且α∈,则sin=()A.- B.- C. D.【回答】A知识点：三角恒等变换题型：选择题...
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![sin造句怎么写]( "sin造句怎么写")
- Doyoucondonehissin?Iguessignorancemustbeasin.JesusChristredeemedmenfromsin.There'snothinginherentlysupernaturalaboutsin.Sostopseeingyourselfassomeonewhohastosin.Stopchoosingsin.Extremeselfishnessistherootofthesinproblem,andwhenyouhavetherootofthesin...
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![—Sir,couldIhandinmyhomeworkabitlate?----- ,sin...]( "—Sir,couldIhandinmyhomeworkabitlate?----- ,sin...")
- 问题详情：—Sir,couldIhandinmyhomeworkabitlate?----- ,sinceyou’vebeenunwellthesedays.A.Youcan’tbeserious B.I’mafraidnotC.Goodidea D.Well,allright【回答】D知识点：交际用语题型：选择题...
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![cos(α－35°)cos(α＋25°)＋sin(α－35°)sin(α＋25°)＝]( "cos(α－35°)cos(α＋25°)＋sin(α－35°)sin(α＋25°)＝")
- 问题详情：cos(α－35°)cos(α＋25°)＋sin(α－35°)sin(α＋25°)＝_____.【回答】.知识点：三角恒等变换题型：填空题...
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![已知0＜＜，sin＝．(1)求tan的值；(2)求cos2＋sin的值．]( "已知0＜＜，sin＝．(1)求tan的值；(2)求cos2＋sin的值．")
- 问题详情：已知0＜＜，sin＝．(1)求tan的值；(2)求cos2＋sin的值．【回答】解：(1)因为0＜＜，sin＝，故cos＝，所以tan＝．(2)cos2＋sin＝1－2sin2＋sin＝－＋＝．知识点：三角函数题型：解答题...
- 30597
![sin（﹣300°）= ．]( "sin（﹣300°）= ．")
- 问题详情：sin（﹣300°）=．【回答】．【考点】诱导公式的作用．【分析】由sin（α+2π）=sinα及特殊角三角函数值解之．【解答】解：sin（﹣300°）=sin（360°﹣300°）=sin60°=，故*为．【点评】本题考查诱导公式及特殊角三角函数值．知识点：三角函数题型：填空题...
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![已知,0＜β＜,cos(－α)=,sin(+β)=,求sin(α+β)的值.]( "已知,0＜β＜,cos(－α)=,sin(+β)=,求sin(α+β)的值.")
- 问题详情：已知,0＜β＜,cos(－α)=,sin(+β)=,求sin(α+β)的值.【回答】∵sin(α+β)=－cos［+(α+β)］=－cos［(+β)－(－α)］=－[cos(+β)cos(－α)+sin(+β)sin(－α)]∵＜α＜ ＜－α＜ ＜－α＜0，0＜β＜ ＜+β＜π.∴sin(－α)===，cos(+β)===.由(1)得: sin(α+β)=－［×+×()］=.知识点：三角恒等变换题型：解答题...
- 22633
![sin，则tan=]( "sin，则tan=")
- 问题详情：sin，则tan=_____________。【回答】－；知识点：三角函数题型：填空题...
- 26314
![deadly sin造句怎么写]( "deadly sin造句怎么写")
- Envyisnotjustadeadlysin,itisalsoanemotionalreality.unreasonableandinordinateself-esteem(personifiedasoneofthedeadlysins).ThemostdeadlysingletornadoinAmericasince1947hitJoplin,Missouri,killingatleast125people.Around900wereinjuredandmoreweremissing.But...
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![已知sin(＋α)＝，则sin(－α)的值为]( "已知sin(＋α)＝，则sin(－α)的值为")
- 问题详情：已知sin(＋α)＝，则sin(－α)的值为________． 【回答】 知识点：三角函数题型：填空题...
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![sin经典语录]( "sin经典语录")
- 经典语录我一直在反复提醒自己，永远不要因为外界因素而改变你的善良。别人没有公德心，污染环境乱闯马路，你也随地吐痰顶着红灯撒丫子跑。别人铺张浪费大手大脚，你也唾沫星子横飞，跟人大谈名表。别人夜夜萧歌左拥右抱，你也顶着洗剪吹往夜店跑，傻逼，这是一种堕落。你得有自己的坚持...
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![mortal sin造句怎么写]( "mortal sin造句怎么写")
- Venialsinormortalsin?Repentancealonedidnotcanceloutsuchmortalsin.IsitamortalsinnottoparticipateinMassonSundaysandholydaysofobligation?Notforanymortalsin,butthewickednessofmyabhorrentface!anunpardonablesinentailingatotallossofgrace;theologianslist7mor...
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![求值：sin(－1200°)·cos1290°＋cos(－1020°)·sin(－1050°)＋tan945°...]( "求值：sin(－1200°)·cos1290°＋cos(－1020°)·sin(－1050°)＋tan945°...")
- 问题详情：求值：sin(－1200°)·cos1290°＋cos(－1020°)·sin(－1050°)＋tan945°．【回答】解：原式＝－sin1200°·cos1290°＋cos1020°·(－sin1050°)＋tan945°＝－sin120°·cos210°＋cos300°·(－sin330°)＋tan225°＝(－sin60°)·(－cos30°)＋cos60°·sin30°＋tan45°＝×＋×＋1＝2．知识点：三角恒等变换题型：解...
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![cardinal sin造句怎么写]( "cardinal sin造句怎么写")
- That'scardinalsinnumberone.Andwe'llsayitagain:Usingthesamepasswordformultipleaccountsisacardinalsininthesecurityworld,somakesureyoumixitup,evenwithaccountsyourarelyuse.InAugust2007,anAirForceunitmistakenlyflewsixnuclearwarheadsacrosstheUSonaB-52—a...
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