1) Просто сопоставить с таблицей
a) -π/2
б) 0
в) -π/3 + 2π/3 = π/3
2)
а)sinx = -1/2
x = (-1)^(n + 1) * π/6 + πk, k ∈ Z
б) cos(x - π/3) = √2/2
x - π/3 = ±π/4 + 2πk, k ∈ Z
x = 7π/12 + 2πn, x = -π/12 + 2πm, n,m ∈ Z
в) tg(3x + π/4) = 1
3x + π/4 = π/4 + πk, k ∈ Z
x = πk
г) cos(x/2) = 0x/2 = π/2 + πk, k ∈ Z
x = π + 2πk