Ответ:
a) ±π/3 + 2πn, n∈Z; b) ±π/2 + 6πn; в) ±π/4 +2πn; г) ±3π +8πn, n∈Z
Пошаговое объяснение:
a) x=±arccos1/2 +2πn
x=±π/3 + 2πn
b) cos(x/3) =√3/2
x/3=±π/6 + 2πn
x= ± π/2 + 6πn
в) x= ± π/4 + 2πn
г) cos(x/4) = - 1/√2
x/4 = ± arccos( - 1/√2) + 2πn
x/4 = ± 3π/4 + 2πn
x = ±3π +8πn, n∈Z