I believe it’s just:
y=SinX
The amplitude is one so therefore it would be y=(1)Sin
And then the frequency is one because from 0 to 540, it goes through a full wavelength once. y=(1)Sin(1)X
You don’t write the one’s, so that’s why I believe that it would be y=SinX
Definitely get a second opinion though, I don’t want to tell you the wrong answer!