高一三角函数化简 cos^2(-α)-(tanα)/(sin(-α))

问题描述:

高一三角函数化简 cos^2(-α)-(tanα)/(sin(-α))
不能再简了吗?

cos^2(-α)-(tanα)/(sin(-α))
=cos^2a-sina/sin(-a)cosa
=cos^2a-sina/-sinacosa
=cos^2a+1/cosa
=(cos^3a+1)/cosa
注:你再找也找不到其他公式了.