\[1)\ y = \arccos\left( \cos x \right)\]
\[0 \leq x \leq \pi:\]
\[y = \arccos\left( \cos x \right)\]
\[y = x.\]
\[Функция\ четная:\]
\[y( - x) = \arccos\left( \cos( - x) \right) =\]
\[= \arccos\left( \cos x \right) = y(x).\]
\[Период\ функции:\]
\[T = 2\pi.\]
\[2)\ y = \arcsin\left( \cos x \right)\]
\[0 \leq x \leq \pi:\]
\[y = \arcsin\left( \cos x \right)\]
\[y = \frac{\pi}{2} - \arccos\left( \cos x \right)\]
\[y = \frac{\pi}{2} - x.\]
\[Функция\ четная:\]
\[y( - x) = \arcsin\left( \cos( - x) \right) =\]
\[= \arcsin\left( \cos x \right) = y(x).\]
\[Период\ функции:\]
\[T = 2\pi.\]