The graph is about a tangent function.
[tex]y=a\tan (bx-c)+d[/tex]
We have to find the parameters a and b.
The period formula is
[tex]P=\frac{\pi}{|b|}[/tex]
If we find the period, we can find b.
Remember that the period is the distance between two consecutive asymptotes. In this case, the period is 2pi.
[tex]\begin{gathered} 2\pi=\frac{\pi}{b} \\ 2=\frac{1}{b} \\ b=\frac{1}{2} \end{gathered}[/tex]
