So I started working on my for my Exam and I wanted to know if I get this graph right!

So a graph is given to me

<<< this is the graph

So I looked for the amplitude and the period..

and I think that the amplitude is

[A]= 2-(-2)=4/2=2, so amplitude is 2

Then the period I am not really sure.... I have 2pi/4=pi/2, so I assume that the period is pi/2

Now The example ask me to Find an equation for sine function for the graph

So I conclude that isy=-2sin(pi/2x-pi/2) since it looks like an inverse curve for sine.and Now it ask me a cosine function

So I conclude that isy= 2cos(pi/2x-pi/2)

PLEASE HELP ME.... I wan't to know if I did it right!