\[1)\cos x = 1 - \frac{2x}{\pi};\]
\[y = \cos x;\ y = 1 - \frac{2x}{\pi}.\]
\[Ответ:\ \ 0;\ \frac{\pi}{2};\ \pi.\]
\[2)\cos x = \sqrt{x - \frac{\pi}{2}}\]
\[y = \cos x;\ y = \sqrt{x - \frac{\pi}{2}}.\]
\[Ответ:\ \ \frac{\pi}{2}.\]
\[3)\cos x = 1 + \sqrt{x - 2\pi}\]
\[y = \cos x;\ y = 1 + \sqrt{x - 2\pi}.\]
\[Ответ:\ \ 2\pi.\]
\[4)\cos x = x + \frac{\pi}{2}\]
\[y = \cos x;\ y = x + \frac{\pi}{2}.\]
\[Ответ:\ - \frac{\pi}{2}.\]