化简sin^2acos^b-cos^2asin^2b+cos^a-cos^2b

分类: 作业答案 • 2022-01-09 18:04:51

问题描述：

答

sin^2acos^2b-cos^2asin^2b+cos^2a-cos^2b
=cos^2b(sin^2a-1)+cos^2a(1-sin^2b)
=cos^2acos^2b-cos^2acos^2b
=0