cos(2пx+п/4)=1/2 пожалуйста

2πx + π/4 = +-arcCos 1/2 + 2πk, k ∈Z
2πx + π/4 = +- π/3 + 2πk , k ∈Z
2πx = +-π/3 + 2πk - π/4 , k ∈Z
x = +-1/6 +k - 1/8, k ∈Z

2πx+π/4=+-π/3+2πn,n∈Z
2πx=-π/4-π/3+2πn,n∈Z U 2πx=π/4-π/3+2πk,k∈Z
2πx=-7π/12+2πn,n∈Z  U  2πx=-π/12+2πk,k∈Z
x=-7/24+n,n∈Z  U  x=-1/27+k,k∈Z