directrix Definition
a fixed straight line used to define or generate a curve such as a parabola or hyperbola.
Using directrix: Examples
Take a moment to familiarize yourself with how "directrix" can be used in various situations through the following examples!
Example
The directrix of a parabola is a line perpendicular to the axis of symmetry.
Example
The directrix of a hyperbola is a line that is equidistant from the two foci.
Example
The directrix of an ellipse is a line that is parallel to the major axis.
directrix Synonyms and Antonyms
Phrases with directrix
focus-directrix property
a property of conic sections that states that the distance from a point on the curve (the focus) to a fixed line (the directrix) is proportional to the distance from that point to another fixed point (the other focus)
Example
The focus-directrix property is used to define and derive properties of conic sections.
a straight line that is perpendicular to the base of a cone and intersects the surface of the cone at a fixed angle
Example
The directrix of a cone is used to define and derive properties of conic sections in three dimensions.
a straight line that is parallel to the base of a cylinder and intersects the surface of the cylinder at a fixed angle
Example
The directrix of a cylinder is used to define and derive properties of conic sections in three dimensions.
Origins of directrix
from Latin 'directus', meaning 'straight'
Summary: directrix in Brief
The term 'directrix' [dɪˈrɛktrɪks] refers to a fixed straight line used to define or generate a curve, such as a parabola or hyperbola. It is a fundamental concept in the study of conic sections, with examples including the focus-directrix property and the directrix of a cone or cylinder.
