sin(x/2 + π/6)=1 cos(2π/3 -x)=?
问题描述：
sin(x/2 + π/6)=1 cos(2π/3 -x)=?
答
sin(x/2 + π/6)=1
则
cos( π/3 - x/2)=cos( π/2 - (x/2 + π/6) )=sin(x/2 + π/6)=1
cos(2π/3 -x)
=2cos²( π/3 - x/2)-1
=2-1
=1