Cut-The-Knot Action 18!
Creation of this applet was inspired by a tweet from Alexander Bogomolny.
Shown below is a rectangular hyperbola.
A rectangular hyperbola is one whose semimajor and semiminor axes are equal.
Thus, its eccentricity .
Suppose a triangle has 3 vertices that lie on such a hyperbola.
How can we prove its orthocenter always lies on this hyperbola as well?