Chapter 4 - Graphs of the Circular Functions - Section 4.3 Graphs of the Tangent and Cotangent Functions - 4.3 Exercises - Page 172: 42

$f(x) = tan~3x$

When $x = 0$, then the value of the function is zero. This is the graph for a tangent function. Compared with a standard tangent function, the first positive asymptote occurs at $x = \frac{\pi}{6}$ instead of $\frac{\pi}{2}$. Therefore we need to include the term $3x$ for the angle in the function. The equation for this graph is: $f(x) = tan~3x$