Hello there, I have been trying to remember some of the properties of the ellipse as we started talking about it in another thread and i realized that it had been so long since i studied this stuff that i had forgotten some of it. The category would be under geometry, elemental two dimensional shapes, conics. There are a host of properties and formulas, such as that the distance from one focus to the curve and from the curve back to the second focus is a constant and this is the idea behind drawing the Ellipse with a length of cord and a pencil, where the two ends of the cord are tacked down and the pencil point is then constrained by the cord so that it can only reach so far away from either focus, and that, if done right, creates an ellipse. There are other properties too, but what i am after is a little different than the usually handful. Since i dont remember much about how this works, i'll ask some very general questions and maybe that will jar my memory and then i can remember some more specific things. I can assure you though that what i am after here is much more interesting than most of the more common properties. I might also mention that there have been several writings on the ellipse that contain several pages, just for this one amazing 2d shape. Compare that to the circle, which although interesting for many reasons in itself still pales in comparison. So without any further delay, let me get down to it. At the heart of this exploration we have the equation for the Ellipse in cartesian coordinates: [EQU 1] y^2/b^2+x^2/a^2=1 and in Latex (latex code not working perhaps): The first two questions are simple and straightforward, and replies may lead to other questions. Question 1: Eliminate either 'a' or 'b' from EQU 1. Question 2: Convert EQU1 to an equation with only one variable instead of both x and y. (Please note that solving for x or y in terms of the other variables and constants is not the same thing). Notes: 'a' and 'b' are considered to be constants, while 'x' and 'y' are considered to be variables. The attachment is a picture file of the EQU 1 formula for easy viewing.