Focus-Directrix Definition

Focus-Directrix Definition

A parabola is the locus of a point whose distance from the focus equals its perpendicular distance from the directrix.

$$SP=PM$$

Terminology

- $$s$$ → Focus.

- $$p$$ → Variable point on the parabola.

- $$PM$$ → Perpendicular distance from $$p$$ to the directrix.

Usage

- Used to derive the equation of a parabola and solve locus-based problems.