Polar equation of a Kepler orbit
= Polar equation of a Kepler orbit
{title2=$r=p/(1+e\cos f)$}
For an attractive <inverse-square force>, $r=p/(1+e\cos f)$, where $f$ is <true anomaly>, $e$ is <orbital eccentricity>, and $p=h^2/\mu$ is the semilatus rectum. The <specific angular momentum> relation $\dot f=h/r^2$ converts this geometric equation into an angular evolution law.