Zadanie 1.
[tex]-1\leq \cos\frac{1}{3}x\leq 1\ |*(-2)\\-2\leq -2\cos\frac{1}{3}x\leq 2\ |+\frac{1}{2}\\-2+\frac{1}{2}\leq -2\cos\frac{1}{3}x+\frac{1}{2}\leq 2+\frac{1}{2}\\-1\frac{1}{2}\leq -2\cos\frac{1}{3}x+\frac{1}{2}\leq 2\frac{1}{2}\\ZW_f= < -1\frac{1}{2},2\frac{1}{2} >[/tex]
Zadanie 2.
[tex]\sin x=\frac{-\sqrt3}{2}\qquad x\in < -2\pi,2\pi >[/tex]
[tex]x=-\frac{2\pi}{3}+2k\pi\vee x=-\frac{\pi}{3}+2k\pi\qquad k\in\mathbb{Z}\\\text{ale }x\in < -2\pi,2\pi > \\x=-\frac{2\pi}{3}\vee x=-\frac{\pi}{3}\vee x=\frac{4\pi}{3}\vee x=\frac{5\pi}{3}\\x\in\{-\frac{2\pi}{3},-\frac{\pi}{3},\frac{4\pi}{3},\frac{5\pi}{3}\}[/tex]
