Date: Sep 12, 2013 9:15 PM
Author: mervynmccrabbe@gmail.com
Subject: Re: Building an Equation to find (Maximum Y) ie Highest Point on a curve!

>Just interchange x and y, then get Max y for the new equation. 

x^4 + y^4 + A(x^2) - A(y^2) + 2(x^2)(y^2) - Bxy + C = 0

By substituting x for y the above equation becomes :-
x^4 + y^4 - A(x^2) + A(y^2) + 2(x^2)(y^2) - Bxy + C = 0

So presumably the new dy/dx becomes:-
dy/dx = -(4x^3 - 2ax + 4xy^2 - by)/(4y^3 + 2ay + 4x^2 y - bx)

and in turn giving
4x^3 - 2ax + 4x(y^2) - by = 0
as the equation to be merged with the xy-altered equation:-
x^4 + y^4 - A(x^2) + A(y^2) + 2(x^2)(y^2) - Bxy + C = 0

Even if i'm right so far, I am again lost in finding the equivalent of
quasi's solution to the original equation.

Thank you for replying Leon

Mervyn