Question

ПРОШУУУУ!!! СРОЧНО НАДО!!! ПОМОГИТЕ!!!

Answer 1

cos2x≥0,5    
cos²x-sin²x≥1/2
cos²x-(1-cos²x)≥1/2
2cos²x≥3/2
cos²x≥3/4
cosx≥+/-√3/2
-π/6+2πn≤x≤π/6+2πn