化简:cot^2A(tan^2A-sin^2A)

来源：学生作业学帮网编辑：学帮网时间：2024/06/16 10:00:53

cos^2A/sin^2A(sin^2A/cos^2A-sin^2A)=1-Cos^2(A)=sin^2A

原式=sin^2a-cos^2a*sin^2a=(sina+cosasina)(sina-sinacosa)