证明：1+cos^2a/sin^2a=1/sin^2aRT
问题描述：
证明：1+cos^2a/sin^2a=1/sin^2a
RT
答
1+cos²a/sin²a
=(sin²a)sin²a+cos²a/sin²a
=(sin²a+cos²a)/sin²a
=1/sin²a
望采纳~
答
1+cos^2a/sin^2a=sin^2a/sin^2a+cos^2a/sin^2a
=（sin^2a+cos^2a）/sin^2a
=1/sin^2a.