Hi,

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

Stonehambey