Each of the following equations in parts (a) & (b) describes r(t) which represents the position of a particle in space at time t. Find the particle's velocity and acceleration vectors. Then find the particle's speed and direction of motion at the given value of t. Write the particle's velocity at that time as the product of its speed and direction. a) r(t) = (sect, tan t, t); t= b) r(t) = (e-t, 2 cos(3t),2 sin(3t)); t=