Directrix of a Parabola Calculator

Parabola Visualization

Understanding Parabola Directrix

In geometry, a parabola is a U-shaped curve that is symmetric. A directrix is a straight line that is used to define a parabola. For any point on the parabola, the distance to the focus is equal to the perpendicular distance to the directrix.

For a vertical parabola $$ (x-h)^2 = 4p(y-k) $$, the directrix is a horizontal line given by the equation $$ y = k - p $$. For a horizontal parabola $$ (y-k)^2 = 4p(x-h) $$, the directrix is a vertical line given by $$ x = h - p $$. Here, (h, k) is the vertex of the parabola, and 'p' is the distance from the vertex to the focus and from the vertex to the directrix.

Use this calculator to easily find the directrix of any parabola and visualize it!