#### Answer

$y = -1+\frac{1}{2}sin~x$
We can see the graph below.
The period is $2\pi$
The amplitude is $0.5$

#### Work Step by Step

$y = -1+\frac{1}{2}sin~x$
When $x = 0$, then $y = -1+\frac{1}{2}sin~0 = -1$
When $x = \frac{\pi}{2}$, then $y = -1+\frac{1}{2}sin ~\frac{\pi}{2} = -0.5$
When $x = \pi$, then $y = -1+\frac{1}{2}sin~\pi = -1$
When $x = \frac{3\pi}{2}$, then $y = -1+\frac{1}{2}sin~\frac{3\pi}{2} = -1.5$
When $x = 2\pi$, then $y = -1+\frac{1}{2}sin~2\pi = -1$
We can see the graph below.
The period is $2\pi$
The amplitude is $0.5$