sin²(π/4+2π/3)等于多少
问题描述：
sin²(π/4+2π/3)等于多少
答
sin²(π/4+2π/3)
=sin²(11π/12)
=[1-cos(11π/6)]/2
=[1-cos(-π/6)]/2
=[1-cos(π/6)]/2
=(1-√3/2)/2
=(2-√3)/4