Упрастите выражение sin 2п/3 cos п/6+cos 2п/3 sin п/6
Sinacosb+cosasinb=sin(a+b) ------------------------------------------- sin2π/3cosπ/6+cos2π/3sinπ/6=sin(2π/3+π/6)=sin5π/6=sin(π-π/6)=sinπ/6=1/2