What is the velocity of the simple harmonic motion problem?

Question

Position of the graph is
y= .4*cos(2pi*1/3*x)+1.2

I need to find the velocity as well as the acceleration. I have worked through it and keep getting that the velocity is 0. I don't believe that is correct.

Answer 1

v = dy/dt
a = dv/dt
Take the first and second derivatives