证明：tan^2a-sin^2a=tan^2*sin^2a

分类: 作业答案 • 2022-01-09 18:05:21

问题描述：

答

tan^2a-sin^2a
=sin^2a/cos^2a-sin^2a
=(sin^2a-cos^2a*sin^2a)/cos^2a
=sin^2a(1-cos^2a)/cos^2a
=sin^2a*sin^2a/cos^2a
=tan^2*sin^2a