42. The cylinder passing through (0, 2, 1) with the vertical line through (1, 0, 0) as its central axis In Exercises 43-50, find a vector parametrization for the line with the given description. 43. Passes through P = (1, 2, -8), direction vector v = (2, 1, 3) 44. Passes through P = (4, 0, 8), direction vector v = (1, 0, 1) 45. Passes through P = (4, 0, 8), direction vector v = 7i + 4k 46. Passes through O, direction vector v = (3, -1, -4) (2, 1, 1) 47. Passes through (1, 1, 1) and (3, -5, 2) 48. Passes through (-2, 0, -2) and (4, 3, 7) 12, 3, 3) 49. Passes through O and (4, 1, 1) 50. Passes through (1, 1, 1) parallel to the line through (2, 0, -1) and (4, 1, 3) In Exercises 51-54, find parametric equations for the lines with the given parallel. description. 51. Perpendicular to the xy-plane, passes through the origin 52. Perpendicular to the yz-plane, passes through (0, 0, 2) 53. Parallel to the line through (1, 1, 0) and (0, -1, -2), passes through (0, 0, 4) 54. Passes through (1, -1, 0) and (0, -1, 2) 55. Which of the following is a parametrization of the line through P = (4, 9, 8) perpendicular to the xz-plane (Figure 19)? (a) r(t) = (4, 9, 8) + t (1, 0, 1) (c) r(t) = (4, 9, 8) + t (0, 1, 0) (b) r(t) = (4, 9,8) + + (0, 0, 1) 2, -1) (d) r(t) = (4, 9,8) + t (1, 1, 0)