Find a vector equation and parametric equations for the line segment that joins P to Q. P(1, - 1, 3), Q(3, 5, 1) vector equation r(t) = (1 + 3t, - 1 + 5t, 3 + t) X parametric equations (x(t), y(t), z(0)) = ( 1 + 3t, - 1 + 5t, 3 + t X