Помогите! Решить уравнение

sinx-sin2x+sin3x=sin4x

Sinx-sin2x+sin3x-sin4x=0

-2cos (3x/2) sin (x/2) - 2cos (7x/2) sin (x/2) = 0

sin0.5x=0 1/2x=πn x=2πn

cox (3x/2) + cos (7x/2) = 0

2cos (10x/2) cos (4x/2) = 0

c0s (5x) = 0 5x=π/2+πn x=π/10+πn/5

cos2x=0 2x=π/2+πn x=π/4+πn/2