trigonometry equation

i didn't understood this topic please explain it
1.)
$ sinx \ge -\frac{1}{2} $
and the answer is

$ -\frac{\pi}{6}+2n\pi\le x \le \frac{7\pi}{6}+2n\pi $

where n belongs to integers
2.)
similarly for below
$ cosx \ge \frac{1}{2} $
and the answer is
$ 2n\pi-\frac{\pi}{3}\le x \le 2n\pi+\frac{\pi}{3} $

where n belongs to integers
Is there any general methodology for this please help me

Back to top