Question

Draw a conic curve when the distance of focus from the directrix is 60mm and eccentricity is 2/3.​

Answer 1

An ellipse is obtained when a section

plane A–A, inclined to the axis cuts all

the generators of the cone.

• A parabola is obtained when a section

plane B–B, parallel to one of the

generators cuts the cone. Obviously, the

section plane will cut the base of the

cone.

• A hyperbola is obtained when a section

plane C–C, inclined to the axis cuts the

cone on one side of the axis.

• A rectangular hyperbola is obtained

when a section plane D–D, parallel to

the axis cuts the cone.