Question

Cos1,5a=cos0,5acosa решить уравнение

Answer 1

$\cos(1.5a ) - \cos(0.5a) = 0$
$- 2 \sin(a) \times \sin( \frac{a}{2} ) = 0$
$\sin(a) \times \sin( \frac{a}{2} ) = 0$
$\sin(a) = 0$
$\sin( \frac{a}{2} ) = 0$
$a = kn$
$a = 2kn$