sin^4x cos^2x+cos^4x sin^2 x=sin^2x*cot^2x 怎么得来

分类: 作业答案 • 2022-01-09 18:01:33

问题描述：

sin^4x cos^2x+cos^4x sin^2 x=sin^2x*cot^2x 怎么得来
sin^4x cos^2x+cos^4x sin^2 x=sin^2x*cot^2x 怎么得来

答

原式等于 sin^2(sin^2+cos^2)+cos^2 = sin^2*(1)+cos^2 = sin^2+cos^2 = 1