Consider the following. r(t) = (7) + (3t2)j + 8tk, P(6, 1, 8) (a) Find the arc length function s(t) for the curve measured from the point P in the direction of increasing t. s(t) = Reparametrize the curve with respect to arc length starting from P. (Enter your answer in terms of s.) r(t(s)) (b) Find the point 3 units along the curve (in the direction of increasing t) from P. (x, y, z) =