cosx = 1/2

x = ±arccos(1/2) + 2πk

x = ± π/3 + 2πk,   k∈Z

Ответ:  ± π/3 + 2πk,   k∈Z

tgx = √3/3

x = arctg(√3/3) + πk

x = π/6 + πk,   k∈Z

Ответ: π/6 + πk,   k∈Z