My wife was looking at the properties of #ellipses such as the one where the sum of the distance of all points on the #ellipse from the two foci are the same and how that relates to the standard equation of an ellipse and so I showed her using my scribbly #handwriting and untidy drawings. Unfortunately, it didn't quite hit home and so I wrote these notes up neatly using #LaTeX, which did do the trick.

To put it up here, I converted the #PostScript pages to #PNG format using #GNU #Gimp and the figure was produced using #Tgif.

#Mathematics #Geometry #TwoDimensional #PlaneCurve #CartesianCoordinates #CCBYSA