数学:第一章《解三角形》测试(1)(新人教A版必修5).pdf
中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献第一章解三角形单元测试一、选择题1.A为 ABC的内角,则AAcossin的取值范围是()A.)2,2(B.)2,2(C.2,1(D.2,22.在 ABC中,若,900C则三边的比cba等于()A.2cos2BAB.2cos2BAC.2sin2BAD.2sin2BA3.在 ABC中,若8,3,7cba,则其面积等于()A.12B.221C.28D.364.在ABC中,090C,00450A,则下列各式中正确的是()A.sincosAAB.sincosBAC.sincosABD.sincosBB5.在 ABC中,若)()(cbbcaca,则A()A.090B.060C.0120D.01506.在 ABC中,若22tantanbaBA,则 ABC的形状是()A.直角三角形B.等腰或直角三角形C.不能确定D.等腰三角形二、填空题1.在 ABC中,若,sinsinBA则A一定大于B,对吗?填 _(对或错)2.在 ABC中,若,1coscoscos222CBA则 ABC的形状是 _.3.在 ABC中,C是钝角,设,coscos,sinsin,sinBAzBAyCx则zyx,的大小关系是_.4.在 ABC中,若bca2,则CACACAsinsin31coscoscoscos_.5.在 ABC中,若,tanlgtanlgtanlg2CAB则 B的取值范围是_.6.在 ABC中,若acb2,则BBCA2coscos)cos(的值是 _.中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献三、解答题1.在 ABC中,若)sin()()sin()(2222BAbaBAba,请判断三角形的形状.2.如果 ABC内接于半径为R的圆,且,sin)2()sin(sin222BbaCAR求 ABC的面积的最大值.3.已知 ABC的 三边cba且2,2CAbca,求:a b c4.在 ABC中,若()()3abc abcac,且tantan33AC,AB边上的高为4 3,求角,A B C的大小与边,a b c的长第一章解三角形中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献参考答案一、选择题1.C sincos2sin(),4AAA而520,sin()144424AAA2.B sinsinsinsinsinabABABcC2sincos2 cos222ABABAB3.D 011cos,60,sin6 322ABCAASbcAV4.D 090AB则sincos,sincosABBA,00045,AsincosAA,004590,sincosBBB5.C 22222201,cos,1202acbbc bcabcAA6.B 22sincossincossin,sincossincoscossinsincossinABABAAABBABBABsin 2sin 2,2222ABABAB或二、填空题1.对,sinsinBA则22ababABRR2.直角三角形21(1 cos21cos2)cos()1,2ABAB21(cos2cos2)cos()0,2ABAB2cos()cos()cos()0ABABABcoscoscos0ABC3.zyx,sincos,sincos,22ABABABBA yz,sinsinsin,cabCAB xy xyz4.1sinsin2sin,2sincos4sincos2222ACACACACACB中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献cos2cos,coscos3sinsin222222ACACACAC则221sinsin4sinsin322ACAC1coscoscoscossinsin3ACACAC22(1 cos)(1 cos)14sinsin22ACAC22222sin2sin4sinsin1 12222ACAC5.)2,32tantantantantan,tantan()tantan1ACBACBACAC2tantantantan()tan1ACBACB3tantantantan2tantan2 tanBBACACB3tan3tan,tan0tan33BBBBB6.122,sinsinsin,bacBACBBCA2coscos)cos(2coscossinsincos12sinACACBBcoscossinsincos1 2sinsinACACBACcoscossinsincos1ACACBcos()cos11ACB三、解答题1.解:22222222sin()sincossin,sin()cossinsinabABaABAabABbABBcossin,sin 2sin2,222cossinBAABABABAB或2等腰或直角三角形2.解:2sinsin2sinsin(2)sin,RAARCCabB222sinsin(2)sin,2,aAcCabB acabb222222022,cos,4522abcabcabCCab2222,2sin2,22,sincR cRCR abRabC中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献22222222,22RRababab ab21222sin,24422RSabCab2max212RS另法:122sin2sin2sin244SabCabRARB222sin2sin2sinsin4RARBRAB212cos()cos()2RABAB22122cos()2222(1)22RABR2max212SR此时AB取得等号3.解:sinsin2sin,2sincos4sincos2222ACACACACACB12147sincos,cos,sin2sincos222424224BACBBBB3,24242BBACACB AC33371sinsin()sincoscossin4444ABBB71sinsin()sincoscossin4444CBBB:sin:sin:sina b cABC)77(:7:)77(4.解:22201()()3,cos,602abc abcac acbacBBtantan33tan(),3,1tantan1tantanACACACACtantan23AC,联合tantan33AC中高考复习精品,为中高考保驾护航!祝您金榜提名!爱心 责任 奉献得tan1tan23tan1tan23AACC或,即000075454575AACC或当0075,45AC时,4 34(3 26),8(31),8sinbcaA当0045,75AC时,4 34 6,4(31),8sinbcaA 当00075,60,45ABC时,8,4(326),8(31),abc当00045,60,75ABC时,8,4 6,4(31)abc.