sin2x+sin3x+sin4x+sin5x=0 [П;2П]
Sin2x+sin3x+sin4x+sin5x= 2 sin3x * cosx + 2 sin4x * cosx = 2cosx * ( sin3x + sin4x) = = 4cosx sin(7x/2) cos(x/2) 4cosx sin(7x/2) cos(x/2) = 0 cos x = 0 или sin(7x/2) = 0 или cos x/2 = 0 x= 3П/2 x = 8П/7 x= П х=10П/7 х=12П/7 х=2П