tana=2 则2sin^2+3cos^2a等于多少tana=2 则2sin^2a+3cos^2a等于多少_数学解答

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

人气：455 ℃　时间：2020-05-22 05:10:26

解答

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