Find a parametric representation for the line passing through the following pairs of points. (a) p_1 = (l, 3, -1) and p_2 = (-4, 1, 2) (b) p, =(-1, 5, 3) and p_2 = (-2, 4, 7) find a parametric representation for the line passing through the following points. (1, 1, -1) and (-2, 1, 3) (-1, 5, 2) and (3, -4, 1) let p = (1, 3, -1) and q = (-4, 5, 2). determine the coordinates of the following points: (a) the midpoint of the line segment between p and q. (b) the two points on this line segment lying one-third and two-thirds of the way from p to q. the point lying one-fifth of the way from p to q. the point lying two-fifths of the way from p to q. if p, q are two arbitrary points in n-space, give the general formula for the midpoint of the line segment between p and q.