Double-click on the movie to PLAY.

Click once to PAUSE.

RELOAD the page or double-click to return to the START of the movie.

Method B1

As P moves towards F, QF and QP both get smaller - it looks as though they might be equal.
[But how do we prove it? I'm not sure that the movie helps with this.]

What happens when P goes beyond F? Does the original situation still apply?
Might it still be the case that QF = QP ?

On the next page we move P in the other direction.