Sinx-sin2x+sin3x-sin4x=0

1) sinx+sin2x+sin3x+sin4x = (sinx+sin3x) + (sin2x+sin4x) = 2sin2x * cosx+2sin3x * cosx = 2cosx (sin2x+sin3x) = 4sin (5x/2) * cos (x/2) * cosx sin (5x/2) = 0 5x/2=p n x=2p n/5cos (x/2) = 0 = > x/2=p / 2+p n э Z = > x=p + 2p ncosx=0 x=p / 2+p n x=p / 2+p n 2p n/5; p (1+2n) ; p (1/2+n), n э Z.