*Answer:* At perihelion and aphelion, the comet's velocity is
perpendicular to its position vector from the Sun. Hence, at these two
special points, the comet's angular momentum (around the Sun) takes the particularly
simple form

Here, is the comet's mass, is its distance from the Sun, and is its speed. According to Kepler's second law, the comet orbits the Sun with

where and are the perihelion distance and speed, respectively, and and are the corresponding quantities at aphelion. We are told that , , and . It follows that