一道数学三角函数化简题

题目

一道数学三角函数化简题
(a sin派/5+b cos派/5)/(a cos派 /5 - b sin派/5)=(tan派/5+ b/a)/(1- b/a﹡ tan派/5)为什么啊.

答案

右=(tanπ/5+b/a)/(1-b/a*tanπ/5)右=(sinπ/5/cosπ/5+b/a)/(1-b/a*sinπ/5/cosπ/5) 分子、分母同乘a*cosπ/5右=(asinπ/5+bcosπ/5)/(a*cosπ/5-bsinπ/5)左=(asinπ/5+bcosπ/5)/(a*cosπ/5-bsinπ/5)所以：左=...