求证:sin^2A+sin^2B-sin^2Asin^2B+cos^2Acos^2B=1题中的^2为平方.
问题描述:
求证:sin^2A+sin^2B-sin^2Asin^2B+cos^2Acos^2B=1
题中的^2为平方.
答
求证:sin^2A+sin^2B-sin^2Asin^2B+cos^2Acos^2B=1
题中的^2为平方.