The tangent function has the following form:

The period of the tangent function is given by:

This means that for the parent tangent function:

The period is:

This number represents the distance between two consecutive vertical asymptotes, as shown in the following graph:
If the period is halved this means that the distance between each consecutive asymptote must be half the distance than pi, therefore, it must be:

Therefore, the graph must be the following:
and thus we determine the graph of the transformed function-.