1-sinx=sinx 2cos2x=2. 5-5sinx=cos2x

1) 1 - sin x = Sin x
2Sin x = 1
Sin x = 1/2
x = (-1)^n arcSin 1/2 + nπ, n∈Z
x = (-1)^n π/6 + nπ,n∈Z
2) 2 Cos x = 2
Cos x = 1
x = 2πk , k∈Z
3) 5 - 5 Sin x = Cos2x
    5 - 5Sin x = 1 - 2Sin² x
    2 Sin² x -5Sin x +4 = 0
Sin x = t
2t² - 5t +4 = 0
D = 1
t1= 3/2
t2 = 1
a) Sin x = 3/2
нет решений
б) Sin x = 1
     x = π/2 + 2πk , k∈Z