5 sin 3x - 9 sin x = 0 _________________________________________________

5sin3x - 9sin x = 0 5(3sinx  - 4sin^3 x) - 9sinx = 0 15sinx - 20sin^3 x - 9 sinx = 0 6sinx - 20sin^3 x = 0 2sinx (3 -10sin^2 x) = 0 a) 2sinx = 0 sinx = 0  x1= πn б) 3 - 10sin^2 x = 0 10sin^2x = 3 sin^2x = 3/10 sinx = +-√(3/10) sinx = √(3/10) x2 = (-1)^n * arcsin(3/10)+πn sinx = -√(3/10) x3 = (-1)^(n+1) * arcsin(3/10)+πn