Polar plane of a pole

Question

Polar plane of a pole A of a sphere is locus of all points R where line through A meets points P and Q on sphere such that 2/AR = 1/AP + 1/AQ. How does polar plane of a pole of a sphere look like? Please provide a 3D view

Answer 1

HINT. Consider the particular case when $P$ is the point on the sphere nearest to $A$. By symmetry, the polar plane must be perpendicular to line $AP$.

For a 3D view, I'd suggest you to use GeoGebra.