cos(-6分之11π)
问题描述：
cos(-6分之11π)
答
cos(-11π/6)
=cos(-2π+π/6)
=cos(π/6)
=√3/2
cos(-6分之11π)
cos(-11π/6)
=cos(-2π+π/6)
=cos(π/6)
=√3/2