Question

cos1,5a=cos0,5acosa решить уравнение

Answer 1

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