Не могу решить( , 8√3 cos 5п /12 cos п/12 sin п/6

Решение
(8√3)сos(5π/12)*сos(π/2)*sin(π/6) =  (4√3)*( 1/2)*(cos(5π/12 - π/12)  + cos(5π/12 + π/12)) = (2√3)* (cos(4π/12 + cos(6π/12)) ( 2√3)*(cosπ/6 + cosπ/2) = 2*√3 * (1/2) = √3