恶心新田惠海:数学问题

来源:百度文库 编辑:中科新闻网 时间:2024/05/14 17:26:43
4sinacos^2a/2=2sina+sin2a
要过程阿.证明啊!!

右边
=2sina+sin2a
=2sina+2sinacosa
=2sina(1+cosa)
=2sina(1+2cos^2(a/2)-1)
=4sina*cos^2(a/2)
=左边