Answer
$y=-1-\sec{x}$
Work Step by Step
The given graph looks like a reflection about the x-axis of the of the secant function $y=\sec{x}$.
This means that the tentative equation of the function whose graph is given is $y=-\sec{x}+d$.
RECALL:
The y-coordinates of the vertices of curves of the secant function $y=\sec{x}$ are $-1$ and $1$.
The y-coordinates of the vertices of the curves of the given function are $-2$ and $0$.
This means that the function involves a $1$-unit downward shift of the parent function.
Thus, the equation of the function whose graph is given must be $y=-\sec{x} -1$ or $y=-1-\sec{x}$.
