化简sin^4x-sin^2x+cos^2x

分类: 作业答案 • 2021-12-28 15:51:17

问题描述：

答

sin^4x-sin^2x+cos^2x
=sin^2x(sin^2x-1)+cos^2x
=-sin^2xcos^2x+cos^2x
=cos^2x(1-sin^2x)
=cos^4x