A piston in an engine oscillates up and down from a rest position as shown. The motion of this piston can be approximated by the function HI) = 0.05cos(13t), where t is time, in seconds, and b 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. It) Find the maximum and minimum velocities and the times at which they occur