In co-ordinate geometry what has the same function to a parabola as a director circle to circle

Question

anonymous · Answer

equation of director circle is X^2 + Y^2= 2a^2
dunno about the parabola!!

anonymous · Answer

Indro actually think what is the fuction of the director circle

anonymous · Answer

what do you mean by "function" of director circle,i know its equation only!!

anonymous · Answer

what is the special charecteristics of the director circle, there lies the answer

anonymous · Answer

yeah, it's got a radius of sqrt 2 units, what else??

anonymous · Answer

If you draw tangents to the circle from any point on the director circle the tangents are mutually perpendicular to each other, that property

anonymous · Answer

Yeah forgot that one!!!

anonymous · Answer

@rajarshi tell mani about that gravitation sum