Найдите область определения: y=arccos(2x-1)+sqrt(1/sqrt(2)-cosx) Пожалуйста!

Решите задачу:

$y=arccos(2x-1)+\sqrt{\frac{1}{\sqrt2}-cosx}\\\\OOF:\; \; \left \{ {{-1 \leq 2x-1 \leq 1} \atop {\frac{1}{\sqrt2}-cosx \geq 0}} \right. \; \left \{ {{0 \leq 2x \leq 2} \atop {cosx \leq \frac{\sqrt2}{2}}} \right. \; \left \{ {{0 \leq x \leq 1} \atop { \frac{\pi}{4}+2\pi n\leq x \leq \frac{7\pi }{4}+2\pi n,\; n\in Z}} \right. \; \to \\\\x\in [-1,-\frac{\pi}{4}\, ]\cup [\, \frac{\pi}{4},1\, ]$

$P.S.\; \; \; \frac{1}{\sqrt2}=\frac{1\cdot \sqrt2}{\sqrt2\cdot \sqrt2}=\frac{\sqrt2}{2}$