hello sir i have a doubt in conic sections what is the meaning of a focus?

Dear Student

Focus in conic section is the point at which all the rays will meet in case the light is reflected through the conic.

In case of parabola which is the locus of a point which moves in a plane in such a way that its distance from a fixed point (not on the line) in the plane is equal to its distance from a fixed straight line in the same plane. THis  fixed point is called the focus and the fixed line the directrix.

Focus lies on axis .

In case of ellipse which  is the set of all points in

a plane, the sum of whose distances from two

fixed points in the plane is a constant. these two fixed points are focii.

Similarly in case of hyperbola there are two focii

Hope it clarify your doubt

Regards

team topper