Expand menu menu_open Minimize Start chapters Home History history History expand_more
{{ item.displayTitle }}
navigate_next
No history yet!
Progress & Statistics equalizer Progress expand_more
Student
navigate_next
Teacher
navigate_next
{{ filterOption.label }}
{{ item.displayTitle }}
{{ item.subject.displayTitle }}
arrow_forward
No results
{{ searchError }}
search
menu_open
{{ courseTrack.displayTitle }}
{{ statistics.percent }}% Sign in to view progress
{{ printedBook.courseTrack.name }} {{ printedBook.name }}
search Use offline Tools apps
Login account_circle menu_open

Focus and Directrix

Concept

Focus and Directrix

To every parabola, there is a point called the focus and a line called the directrix. The focus is located on the interior part of the axis of symmetry and the directrix is perpendicular to the axis of symmetry.

The focus and directrix are equidistant from every point on the on the parabola.