tana=2 则2sin^2+3cos^2a等于多少

分类: 作业答案 • 2021-12-28 15:24:43

问题描述：

tana=2 则2sin^2+3cos^2a等于多少
tana=2 则2sin^2a+3cos^2a等于多少

答

2sin^2a+3cos^2a
=(2sin^2a+3cos^2a)/1
=(2sin^2a+3cos^2a)/(sin^2a+cos^2a) 分子分母同时除以cos^2a
=(2tan^2a+3)/(tan^2a+1) tana=2
=(8+3)/(4+1)
=11/5