√2+2×cos(5x+π/3)=0 Помогите пожалуйста

Question

√2+2×cos(5x+π/3)=0
Помогите пожалуйста

Answer 1

√2+2×cos(5x+π/3)=0
2×cos(5x+π/3)= - √2
cos(5x+π/3)= -√2/2
5x + π/3 = +-arcCos(-√2/2) + 2πk , k ∈ Z
5x = -π/3 +- 3π/4 + 2πk , k ∈ Z
x = -π/15 +- 3π/20 + 2πk/5, k∈Z