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证明下列恒等式tan(x+y)/tan(x-y)=sin(x+y)/sin(x-y)
题目详情
证明下列恒等式tan(x+y)/tan(x-y)=sin(x+y)/sin(x-y)
▼优质解答
答案和解析
Tan(x+y) /Tan(x-y) =〔Sin(x+y)/Cos(x+y)〕 /〔Sin(x-y)/Cos(x-y)〕 =〔(SinxCosy+CosxSiny)(CosxCosy+SinxSiny)〕 /〔(CosxCosy-SinxSiny)(SinxCosy-CosxSiny)〕 =（Cosy^2*SinxCosx+Si...
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