Question

一只tanα=根号3,求(2sinα-3cosα)/(sinα+cosα)的值

Answer 1

(2sinα-3cosα)/(sinα+cosα)

=(2tanα-3)/(tanα+1) 这一步是分子分母同除以cosα

=(2√3 -3)/(√3+1)

=(2√3-3)(√3-1)/[(√3+1)(√3-1)]

=(9-5√3)/2