The motion of the piston can be approximated by the function h(t) = 0.05cos13t, where t is time in seconds, and h(t) is the displacement of the piston head from rest position, in metres, at time t. (a) Determine an equation for the velocity of the piston head as a function of time.
[1]

(b) Find the maximum and minimum velocities, and the times at which they occur
using k ∈ Z. [4] (Hint: critical numbers come from the derivative of the function you are trying to find max/mins for)