Discussing properties of a ellipse.
Derivation of the polar equation of an ELLIPSE with radial distance referenced from the center of the ellipse to a point on the locus and angle measured counter-clockwise with respect to the positive semi-major x-axis.
Other discussion on ellipses can be found at the beginning of this video called Flat Earth Answers ans Explanations:
https://www.youtube.com/watch?v=7IQTcmwRMhE
