Question

Помогите решить!!!!!!

54 sin(-28pi3) * cos(23pi6) =

Answer 1

$frac{54}{sin(-frac{28pi }{3})cdot cosfrac{23pi }{6}}= frac{54}{-sin(9pi +frac{pi}{3})cdot cos(4pi -frac{pi}{6})} = -frac{54}{-sinfrac{pi}{3}cdot cosfrac{pi}{6}} =\\= frac{54}{frac{sqrt3}{2}cdot frac{sqrt3}{2}} = frac{54cdot 4}{3} =18cdot 4=72$