0\\\\t=cosx\; ,\; \; |t|\leq 1\; ,\; \; t^2-2t>0\; \; \; ,\; \; t\, (t-2)>0\; ,\\\\znaki:\; \; +++(0)---(2)+++\; \; ,\; \; \; \left [ {{t>2} \atop {t<0}} \right. \; \; \left [ {{cosx>2} \atop {cosx<0}} \right. \; \; \to \; \; cosx<0\; ,\\\\\frac{\pi}{2}+2\pi n<x<\frac{3\pi }{2}+2\pi n\; ,\; n\in Z\\\\5a)\; \; 4sin\frac{x}{2}\geq 3\; \; \to \; \; sin\frac{x}{2}\geq \frac{3}{4}\\\\arcsin\frac{3}{4}+2\pi n\leq \frac{x}{2}\leq \pi -arcsin\frac{3}{4}+2\pi n\; ,\; n\in Z\\\\2\pi -2arcsin\frac{3}{4}+4\pi n\leq x\leq 2arcsin\frac{3}{4}+4\pi n\; ,\; n\in Z" alt="4)\; \; cos^2x-2cosx>0\\\\t=cosx\; ,\; \; |t|\leq 1\; ,\; \; t^2-2t>0\; \; \; ,\; \; t\, (t-2)>0\; ,\\\\znaki:\; \; +++(0)---(2)+++\; \; ,\; \; \; \left [ {{t>2} \atop {t<0}} \right. \; \; \left [ {{cosx>2} \atop {cosx<0}} \right. \; \; \to \; \; cosx<0\; ,\\\\\frac{\pi}{2}+2\pi n<x<\frac{3\pi }{2}+2\pi n\; ,\; n\in Z\\\\5a)\; \; 4sin\frac{x}{2}\geq 3\; \; \to \; \; sin\frac{x}{2}\geq \frac{3}{4}\\\\arcsin\frac{3}{4}+2\pi n\leq \frac{x}{2}\leq \pi -arcsin\frac{3}{4}+2\pi n\; ,\; n\in Z\\\\2\pi -2arcsin\frac{3}{4}+4\pi n\leq x\leq 2arcsin\frac{3}{4}+4\pi n\; ,\; n\in Z" align="absmiddle" class="latex-formula">
