Как решить? Cos2x-1/2=0

Question

Как решить?
Cos2x-1/2=0

Answer 1

Cos2x = 1/2
2x =  ± arccos(1/2) + 2pik
2x = ± pi/3 + 2pik
x = ± pi/6 + pik, k ∈ Z