Question

cos 8П/15× cos П/5 +sin 8П/15×sinП/5​

Answer 1

Ответ:$\frac{1}{2}$

Объяснение:

cos(t)*cos(s)+sin(t)*sin(s)= cos(t-s)

$cos(\frac{8\pi }{15}-\frac{\pi }{5} )=cos(\frac{\pi }{3})\\ cos(\frac{\pi }{3} )=\frac{1}{2}$