Answer
$y = 1-2~csc~(x+\frac{\pi}{2})$
We can see the graph below.
Work Step by Step
$y = 1-2~csc~(x+\frac{\pi}{2})$
When $x = -\frac{\pi}{2}$, then $y = 1-2~csc~0~~$ (which is undefined)
When $x = 0$, then $y = 1-2~csc~\frac{\pi}{2} = -1$
When $x = \frac{\pi}{2}$, then $y = 1-2~csc~\pi~~$ (which is undefined)
When $x = \pi$, then $y = 1-2~csc~\frac{3\pi}{2} = 3$
When $x = \frac{3\pi}{2}$, then $y = 1-2~csc~2\pi~~$ (which is undefined)
We can see the graph below.