Question

Tan 的3角之和公式Tan a加b加c

Answer 1

tan(a + b + c)= sin(a + b + c)/cos(a + b + c)= [sina*cos(b + c) + cosa*sin(b + c)] / [cosa*cos(b + c) - sina*sin(b + c)]分子= sina*(cosb*cosc - sinb*sinc) + cosa*(sinb*cosc + cosb*sinc)= sina*cosb*cos...