(\phi f)(x) := \left \{ \begin{array}{cl}
\operatorname{tg} x & ,\quad x\in \langle -\frac{\pi}{2}+2k\pi, \frac{\pi}{2}+2k\pi \rangle , \; k\in \mathbb{Z} \\
f(x-(2k+1)\pi) & ,\quad x\in \langle -\frac{\pi}{2}+(2k+1)\pi, \frac{\pi}{2}+(2k+1)\pi \rangle , \; k\in \mathbb{Z} \\
0 & ,\quad inace
 \end{array}