In SHM, the general equations for position, velocity, and acceleration are:
x(t) = A cos(ωt + φ)
v = dx/dt = -Aω sin(ωt + φ)
a = d2x/dt2 = -Aω2 cos(ωt + φ)
Whatever is multiplying the sine or cosine represents the maximum value of the quantity. Thus:
xmax = A
vmax = Aω
amax = Aω2
Graphing the position, velocity, and acceleration allows us to see some of the general features of simple harmonic motion: