Answer
$f(x) = -2~tan~x$
Work Step by Step
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 positive and negative values are reflected so this is the graph for a negative tangent function.
The magnitude of the value of the function at $x = \frac{\pi}{4}$ is 2, which is twice the value of the standard tangent function.
The equation for this graph is: $f(x) = -2~tan~x$
