求证:tan^2α-sin^α=tan^2乘sin^2α_数学解答

求证:tan^2α-sin^α=tan^2乘sin^2α

人气：213 ℃　时间：2020-04-08 22:16:47

解答

用a代替
左边=sin²a/cos²a-sin²a
=sin²a(1/cos²a-1)
=sin²a(1-cos²a)/cos²a
=sin²a*sin²a/cos²a
=sin²atan²a
=右边
命题得证