sin^2a乘以tana+cos^2a乘以cota+2sina乘以cosa-cota

分类: 作业答案 • 2021-12-18 22:40:59

问题描述：

答

=sina(1-cos^2a)/cosa+cosa(1-sin^2a)/sina
+2sinacosa-cota
=tana-sinacosa+cota-cosasina+2sinacosa-cota
=tana

答

(1-cos^2a)sina/cosa+(1-sin^2a )cosa/sina+2sina cosa-cota
=sina/cosa+cosa/sina-cosa/sina
=(1-cos^2a)/(sina cosa)
=tana