化简3.cos(27+α)cos(33-α)-sin(27+α)sin(33-α)

分类: 作业答案 • 2022-01-09 18:01:33

问题描述：

化简3.cos(27+α)cos(33-α)-sin(27+α)sin(33-α)
化简cos(27+α)cos(33-α)-sin(27+α)sin(33-α)

答

cos(27°+α)cos(33°-α)-sin(27°+α)sin(33°-α)
=cos[(27°+α)+(33°-α)]
=cos60°
=1/2