Question

Помогите пожалуйста. cos(-x/3)=√2/2

Answer 1

cos(-x/3) = √2/2
-x/3 = ±π/4 + 2πn, n ∈ Z
-x = ±3π/4 + 6πn, n ∈ Z.
x = ±5π/4 + 6πn, n ∈ Z.