When considering the gravity between the Sun and a planet located at its elliptical orbit, substituting the

polar equation of the ellipse into the law of gravity, if the planet's parameters are given (equal to [e.sub.0] and [a.sub.0]), and the mass of the planet is also given (equals to [m.sub.0]), then the following "line solution" can be reached, and it is suitable for the entire elliptical orbit.

Suppose that [B.sub.n] is a set which is bounded, symmetric with the respect of the real axis and which the boundary coincides with the segment [-i, i] and the arc given by the

polar equation [rho] = r([theta])[e.sup.i[theta]], where

It is instructive to note that equation (3.7) reduces satisfactorily to the

polar equation of motion in Schwarzschild's gravitational field when f(r, [theta]) reduces to f(r).

This activity explores the

polar equation of rose curves.