Category:Definitions/Latus Rectum

This category contains definitions related to Latus Rectum.
Related results can be found in Category:Latus Rectum.

Definition

Definition 1

A latus rectum of a conic section $K$ is a chord of $K$ passing through a focus of $K$ perpendicular to the major axis of $K$.

Definition 2

A latus rectum of a conic section $K$ is a chord of $K$ passing through a focus of $K$ parallel to the directrix of $K$.

Examples

Latus Rectum of Circle

The circle, being a degenerate ellipse whose foci coincide, properly has no latus rectum, as a circle has neither a directrix nor a major axis.

However, there is a case to make that, in a sense, a diameter of a circle $C$ can be considered as a latus rectum of $C$.

Latus Rectum of Ellipse

A latus rectum of an ellipse $K$ is a chord of $K$ passing through a focus of $K$ perpendicular to the major axis of $K$.

Latus Rectum of Parabola

A parabola has only one focus, and does not have a minor axis, so the major axis is referred to just as the axis, hence the revised definition:

The latus rectum of a parabola $P$ is the chord of $P$ passing through the focus of $P$ perpendicular to the axis of $P$.

Latus Rectum of Hyperbola

A latus rectum of a hyperbola $K$ is a chord of $K$ passing through a focus of $K$ perpendicular to the major axis of $K$.

Also defined as

Some sources define the latus rectum with respect to the parabola only.

Also see

• Equivalence of Definitions of Latus Rectum

• Results about the latus rectum can be found here.

Linguistic Note

The term latus rectum is a compound of the Latin:

latus, meaning side

rectum, meaning straight or right, as in straight line or right angle.

Hence it literally means right side or straight side.

Its plural is latera recta.

Sources

There are no source works cited for this page. Source citations are highly desirable, and mandatory for all definition pages. Definition pages whose content is wholly or partly unsourced are in danger of having such content deleted. To discuss this page in more detail, feel free to use the talk page.