cosx\3=1\2
х/3 = +/- arccos1/2 + 2πn
x/3 = +/- π/3 + 2πn |*3
x = +/- π + 6πn
x = π + 6πn
x = - π + 6πn, n ∈ Z
cosx\3=1\2
х/3 = +/- arccos1/2 + 2πn
x/3 = +/- π/3 + 2πn |*3
x = +/- π + 6πn
x = π + 6πn
x = - π + 6πn, n ∈ Z