1)3x - π/6 = +-arcCos(-1/2) + 2πk , k ∈Z
3x = π/6 +-2π/3 + 2πk , k ∈Z
x = π/18 +-2π/9 + 2πk/3 , k ∈Z
2) π/4 - x/3 = -π/2 + 2πk , k ∈Z
-x/3 = -π/4 - π/2 +2πk , k ∈Z
x = 3π/4 +3π/2 + 6πk , k ∈Z
3) 4Cos²x = 3
Cosx = +-√3/2
a) Cosx = √3/2
x = +-π/6 + 2πk , k ∈Z
б) Cosx = -√3/2
x = +-5π/6 + 2πn , n ∈Z