At time t = 0, a particle is located at the point (7,3,2). It travels in a straight line to the point (4,8,1), has speed 4 at (7,3,2) and constant acceleration - 3i + 5j - k. Find an equation for the position vector r(t) of the particle at time t. . . . The equation for the position vector r(t) of the particle at time t is r(t) = ( i + () j + () k. (Type exact answers, using radicals as needed.)