#geometry A **parabola** is the set of all points in the plane that are equidistant from a fixed point $\LARGE F$ (the **focus**) and a fixed line $\LARGE l$ (the **directrix**) ![[Pasted image 20240930233004.png]] ![[Pasted image 20240930233419.png]] ## Standard equation ![[Pasted image 20240930233638.png]] $$\LARGE y=\frac{x^2}{4p}$$ Properties: Focus is at $\LARGE F(0,p)$ Directrix is at $\LARGE y=-p$ The line segment that runs through the focus perpendicular to the axis, with endpoints on the parabola, is called the **latus rectum**, and its length is the **focal diameter** of the parabola. ![[Pasted image 20240930234126.png]] Focal diameter is $\LARGE 4p$ (obvious)