解説Parabola as a limit of ellipses and hyperbolas.png
English: A parabola can be seen as the limit curve of a pencil of ellipses and hyperbolas with a common vertex and a common focus, as the other focus is moved to infinity.
A parabola can be seen as the limit curve of a pencil of ellipses and hyperbolas with a common vertex and a common focus, as the other focus is moved to infinity.