sin(80°+3α)cos(35°＋α)-cos(80°﹢3α﹚sin﹙35°﹢3α﹚
=sin[(80°+3α)-(35°＋α)]
=sin(80°+3α-35°-α)]
=sin(45°+2α)最后一个是sin﹙35°﹢3α﹚，不是sin﹙35°﹢α﹚，能用公式做么如果是sin﹙35°﹢3α﹚，不是sin﹙35°﹢α﹚就不能用公式做可能题目有问题