Question 1184288
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The foci of the ellipse  {{{x^2/9}}} + {{{y^2/4}}} = 1  are the points  (-c,0)  and  (c,0)  on  x-axis,  where c = {{{sqrt(9-4)}}} = {{{sqrt(5)}}}.



The locus of points P such that the foci subtend the right angle at point P is the circle, 

centered at the origin of the coordinate plane  and having the radius of  {{{sqrt(5)}}},  EXCLUDING

the endpoints of its diameter that lie on x-axis.
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Solved, answered and explained.