So let and be points on the standard ellipse. I'm trying to show that if subtends a right angle at the point then the chord passes through a fixed point on the x-axis.
So far I've gotten that and I need to show that this is invariant. The condition (that P - (a, 0) - Q forms a right angle) gives me
I've messed around with this for well over 2 hours and all I've gotten into is a terrible mess with some very tedious algebra and nothing to show for it!
Any help would be much appreciated, thanks :)