Question

Найдите. sin390°. cos750°. sin540°.

Answer 1

$sin390 = sin(30 + 360) = sin30 = frac{1}{2}$
$cos750 = cos(2 times 360 + 30) = cos30 = frac{ sqrt{3} }{2}$
$sin540 = sin(360 + 180) = sin180 = 0$