решить уравнение 1-cos x = 2sin x/2

x/2 заменяем на t

1-cos2t-2sint=0

1 - (1-2sin^2t) - 2sint=0

1-1+2sn^2t-2sint=0

sin^2t-sint=0

sint (sint-1) = 0

sint=0 sint=1

t = (pi) * k t = (pi) / 2+2 (pi) * n

x=2 (pi) * k x = (pi) + 4 (pi) * n