Finding the eccentricity of an ellipse when a line joining the foot of the perpendiculars from a point of a known ellipse (having eccentricity e) at 2 perpendicular lines(example the x and y axes ;they are not necessarily the axes of the known ellipse) is a normal to the unknown ellipse -
Can anyone give a hint on how to go about this one? Is using the condition of normality sufficient to approach this? Or is there a better way?
Thanks a lot.