# Directrix and Focus

- Author:
- chisanga

The graph shows a parabola defined by where is a constant and is a parameter. Vary to see how the parametric curve is traced out by a point that depends on . Change to see how the curve changes shape, dependent on this constant.

The , and the directrix and focus?

*directrix*is the blue line and the*focus*is the point A. What is the relationship between the constant,