Find the curvature of the twisted cubic r (t) =< t, t², t³ > at the general point and at (0, 0, 0)

Show that the ellipse x = a cos t, y = b sin t, a 7 b 7 0, has its largest curvature on its major axis and its smallest curvature on its minor axis. (As in Exercise 17, the same is true for any ellipse.)