1)
0\\2cos\frac{x}{2}<1\\cos\frac{x}{2}<\frac{1}{2}\\\frac{\pi}{3}+2\pi{n}<\frac{x}{2}<\frac{5\pi}{3}+2\pi{n}\\\frac{2\pi}{3}+4\pi{n}<{x}<\frac{10\pi}{3}+4\pi{n}" alt="1-2cos\frac{x}{2}>0\\2cos\frac{x}{2}<1\\cos\frac{x}{2}<\frac{1}{2}\\\frac{\pi}{3}+2\pi{n}<\frac{x}{2}<\frac{5\pi}{3}+2\pi{n}\\\frac{2\pi}{3}+4\pi{n}<{x}<\frac{10\pi}{3}+4\pi{n}" align="absmiddle" class="latex-formula">
2)
-\frac{1}{\sqrt{3}}\\-\frac{\pi}{6}+\pi{k}-\frac{1}{\sqrt{3}}\\-\frac{\pi}{6}+\pi{k}