设cos=-3/5,求(tanαcos^3（α）)/(1-sinα)
问题描述：
设cos=-3/5,求(tanαcos^3（α）)/(1-sinα)
答
设cosα=-3/5,求(tanαcos^3（α）)/(1-sinα)因为：cosα=-3/5所以：sinα=(1-cos^2(α))^0.5=(1-9/25)^0.5=(16/25)^0.5=4/5 (tanαcos^3(α))/(1-sinα)=(sinαcos^2(α))/(1-sinα)=(sinα(1-sin^2(α)))/(1-sin...