A hypothetical moon orbits a planet which in turn orbits a star. Suppose that
the orbits are circular and that the moon orbits the planet 12 times in the
time it takes for the planet to orbit the star once. In this problem we will
investigate whether the moon could come to a stop at some instant. (See Figure
4.1 \(12 .)\)
(a) Suppose the radius of the moon's orbit around the planet is 1 unit and the
radius of the planet's orbit around the star is \(R\) units. Explain why the
motion of the moon relative to the star can be described by the parametric
equations \(x=R \cos t+\cos (12 t), \quad y=R \sin t+\sin (12 t)\)
(b) Find values for \(R\) and \(t\) such that the moon stops relative to the star
at time \(t\)
(c) On a graphing calculator, plot the path of the moon for the value of \(R\)
you obtained in part (b). Experiment with other values for \(\bar{R}\)