1. ## degenerate

What degenerate form or forms of the parabola CANNOT be obtained from the intersection of a plane and a double napped cone?

I have to use a diagram and give complete description how to obtain this ( or these) form(s)

how would I do this question ?

2. Originally Posted by brandy
What degenerate form or forms of the parabola CANNOT be obtained from the intersection of a plane and a double napped cone?

I have to use a diagram and give complete description how to obtain this ( or these) form(s)

how would I do this question ?
A degeneate is a the empty set (no intersection which seems impossible), a pairs of intersecting lines or a point. The way you get a pair of intersection lines is by passing a plane perpendicular to the cone base, but that is a type of hyperbola shape. So that point is the only thing you can get, by passing a plane parrallel with with the side of the cone through the vertex of the double cone.

This is mine 33th Post!!!

3. ## ???

I am a little bit confused what diagram would I use?