cos(30°+α)cosα+sin(30°+α)的值与α无关
问题描述:
cos(30°+α)cosα+sin(30°+α)的值与α无关
答
cos(30°+α)cosα+sin(30°+α)﹦cos30°cos²α-sin30°sinαcosα+sin30°cosα+cos30°sinα﹦√3/2cos²α-1/2sinαcosα+1/2cosα+√3/2sinα与α的值是有关系的
答
不对,应该cos(30°+α)cosα+sin(30°+α)sinα=cos30度