Использую
\begin{equation*}
\begin{split}
F^{-1}(0) = \{&0, \pm \pi, \pm 2\pi, \dots \} \subset \mathbb{R}\\
F\bigg(\frac{\pi}{2}\bigg) = 1\\
F([0, \pi]) = &[0,1]\\
F^{-1}([0,1]) &= \bigcup\limits_{\mathbb{R}} [2\pi n, \pi + 2\pi n]
\end{split}
\end{equation*}