directrix

Noun

Meaning

A directress.

A line along which a point in another line moves, or which in any way governs the motion of the point and determines the position of the curve generated by it; the line along which the generatrix moves in generating a surface.

A straight line so situated with respect to a conic section that the distance of any point of the curve from it has a constant ratio to the distance of the same point from the focus.

Synonyms

Antonyms

Phrases with the word

Derivatives

Anagrams

Examples

Directrix and focus A hyperbola can be defined as the locus of points for which the ratio of the distances to one focus and to a line (called the directrix) is a constant e that is larger than 1. This constant is the eccentricity of the hyperbola. Source: Internet

Correspondingly, since C is on the directrix, the y-coordinates of F and C are equal in absolute value and opposite in sign. Source: Internet

Deductions Measured along the axis of symmetry, the vertex, A, is equidistant from the focus, F, and from the directrix. Source: Internet

Conversely, two tangents which intersect on the directrix are perpendicular. Source: Internet

A second equivalent method of constructing an ellipse using a directrix is shown on the plot as the three blue lines. Source: Internet

Equations Cartesian In the following equations and are the coordinates of the vertex of the parabola and is the distance from the vertex to the focus and the vertex to the directrix. Source: Internet

Close letter words and terms