(sin^2x-2sinx*cosx-cos^2x)/(4cos^2x-3sin2x）,已知tanx=2,求值_数学解答

(sin^2x-2sinx*cosx-cos^2x)/(4cos^2x-3sin2x）,已知tanx=2,求值

人气：325 ℃　时间：2019-11-09 03:03:23

解答

(sin^2x-2sinx*cosx-cos^2x)/(4cos^2x-3sin2x)=(sin^2x-2sinx*cosx-cos^2x)/(4cos^2x-6sinxcosx)分子分母同时除以cos^2x=(sin^2x/cos^2x-2sinx*cosx/cos^2x-cos^2x/cos^2x)/(4cos^2x/cos^2x-6sinxcosx/cos^2x)=(tan^...