Question

Помогите решить!!!!!! 54 \ sin(-28pi\3) * cos(23pi\6) =

Answer 1

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