|cosx|

Question

|cosx|

Answer 1

[cosx≤-1/2⇒x∈[2π/3+2πn;4π/3+2πn,n∈z]
[cosx≥1/2⇒x∈[-π/3+2πn;π/3+2πn,n∈z]
x∈[-π/3+2πn;π/3+2πn,n∈z] U [2π/3+2πn;4π/3+2πn,n∈z]