cos 负6分之7派等于多少
问题描述：
cos 负6分之7派等于多少
答
大约0.866025...
答
我的结果不一样啊
cos是偶函数
cos(-7/6派)
=-cos(7/6派)
=-cos(派+1/6派)
=cos(1/6派)
=cos(60度)
=1/2
答
=cos(5π/6-2π)=cos(5π/6)=-√3/2
答
cos(-7π/6)
=cos(7π/6)
=cos(π-π/6)
=-cos(π/6)
=-√3/2
答
负二分之根号三