Question

一道高一数学化简：（sin7+cos15*sin8)/cos7-sin15*sin8

°漏打了，这里的都是角度制。

Answer 1

=[sin(15-8)+cos15sin8]/[cos(15-8)-sin15sin8]
=(sin15cos8-cos15sin8+cos15sin8)/(cos15sin8+sin15cos8-sin15sin8)
=sin15/cos15
=tan15
=tan(45-30)
=[tan45-tan30]/[1-tan45*tan30]
=[1-根号3/3]/(1-根号3/3)
=2-根号3