(sin15°cos15°)/(cos^2 165°- sin^2 165°)计算_数学解答

(sin15°cos15°)/(cos^2 165°- sin^2 165°)计算

人气：403 ℃　时间：2020-06-14 07:29:09

解答

(sin15°cos15°)/(cos^2 165°- sin^2 165°)
=(2sin15cos15)/[2(cos2*165)]
=sin30/2cos330
=sin30/2cos(360-30)
=sin30/2cos30
=1/2*tan30
=√3/6