The locus of the middle point of chords of the ellipse x2/a2+y2/b2=1 whose pole lies on the auxiliary circle is
The points on the ellipse x2/25+y2/9=1 whose angles differ by a right angle are
The locus of the middle point of chords of the ellipse x2/a2+y2/b2=1 which are at a constant distance d from the centre of the ellipse is