Let P(x0, y0), obviously y≠0 (that is, p is not on the X axis), and make a straight line PQ to make Q on the X axis.
According to the inverse theorem of the angular bisector theorem, it can be proved that PQ is the bisector of ∠ F 1/QF2 or PF 1*QF2=PF2*QF 1
So please calculate the length of the four line segments by yourself. The amount of calculation is a bit large, but it is not difficult. It's a mess here Do it yourself