Question

алгебра, помогите пожалуйста

Answer 1

$2Cosx\geq \sqrt{3}\\\\Cosx\geq\frac{\sqrt{3} }{2}\\\\-arcCos\frac{\sqrt{3}}{2}+2\pi n\leq x \leq arcCos\frac{\sqrt{3}}{2}+2\pi n,n\in Z\\\\-\frac{\pi }{6}+2\pi n \leq x \leq \frac{\pi }{6}+2\pi n,n\in Z\\\\\boxed{x\in[-\frac{\pi }{6}+2\pi n \ ; \ \frac{\pi }{6}+2\pi n] ,n \in Z}$