Answer
$y = 2+cos~x$
We can see the graph below.
Work Step by Step
$y = 2+cos~x$
When $x = 0$, then $y = 2+cos~0 = 3$
When $x = \frac{\pi}{2}$, then $y = 2+cos~\frac{\pi}{2} = 2$
When $x = \pi$, then $y = 2+cos~\pi= 1$
When $x = \frac{3\pi}{2}$, then $y = 2+cos~\frac{3\pi}{2} = 2$
When $x = 2\pi$, then $y = 2+cos~2\pi = 3$
We can see the graph below.