An object moves on a trajectory given by r(t) = (15 cos 4t,15 sin 4t) for 0 t pi. How far does it travel? The object travels units. (Type an exact answer, using n as needed.) Find the length of the following two-dimensional curve. r(t) = (2 cos t + 2t sin t,2 sin t - 2t cos t) for 0 t pi/2 L = (Type an exact answer, using n as needed.) Find the length of the following three-dimensional curve, r(t) = (1 + 5t,4 - 2t - 7 + 2t>, for 1 t 8 L = (Type an exact answer, using radicals as needed.)