已知1+tanx/1-tanx=3 求sin2x+2sinx·cosx-cos2x/sin2x+2cos2x已知(1+tanx)/(1-tanx)=3 求(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)的值

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已知1+tanx/1-tanx=3 求sin2x+2sinx·cosx-cos2x/sin2x+2cos2x已知(1+tanx)/(1-tanx)=3 求(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)的值
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已知1+tanx/1-tanx=3 求sin2x+2sinx·cosx-cos2x/sin2x+2cos2x已知(1+tanx)/(1-tanx)=3 求(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)的值
已知1+tanx/1-tanx=3 求sin2x+2sinx·cosx-cos2x/sin2x+2cos2x
已知(1+tanx)/(1-tanx)=3 求(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)的值

已知1+tanx/1-tanx=3 求sin2x+2sinx·cosx-cos2x/sin2x+2cos2x已知(1+tanx)/(1-tanx)=3 求(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)的值
先对(1+tanx)/(1-tanx)=3进行处理~1+tanx=3-3tanx~tanx=1/2
然后把(sin^2x+2sinx·cosx-cos^2x)/(sin^2x+2cos^2x)中的每一项同时除cos^2x得
(tan^2x+2tanx-1)/(tan^2x+2)
在把tanX=1/2代入得1/9