How do I find max?

[Butch]

In this desmos graph:

https://www.desmos.com/calculator/f607tsq5ux

I need to find max for the elliptical paths of rab and rcd so that I can determine the foci... I have researched on the web finding max of a function, but just cannot seem to get my head around it. Would greatly appreciate some help.

[mathematic]

It looks like the min and max occur when sin = 0 (0 or 180).

[Butch]

Saw it that way myself... had some problem programmatically, don't recall what it was exactly, thx for taking a look.

Edited June 23, 2021 by Butch