Parabola with directrix and focus

Parabolas A parabola is the set of all points (x, y) in a plane that are equidistant from a fixed line, the directrix, and a fixed point, the focus, not on the line. The midpoint between the focus and the directrix is the vertex, and the line passing through the focus and the vertex is the axis of the parabola.The standard form of the equation of a parabola with vertex at (h, k) (x – h)² = 4p(y – k), p ≠ 0       vertical axis, directrix y = k – p (y – k)² = 4p(x – h), p ≠ 0       horizontal axis, directrix x = h – pThe focus lies on the axis p units (directed distance) from the vertex. If the vertex is at the origin (0, 0), then the equation takes one of the following forms. x² = 4py y² = 4px