Question

3 sin²x-5 sin x-2=0

Answer 1

$3 sin^{2}x - 5sinx -2$
Sin x заменяем на t
$3t^{2}-5t-2$
$t_{1} = 12:6 = 2$ - не подходит |sinx| ≤ 1
$t_{2} = frac{-2}{6} = frac{-1}{3}$

$sinx = frac{-1}{3}$
x=arcsin(-1/3) + 2 πn
x= π - arcsin(-a/3) + 2 πn