directrix of a conic

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• Directrix — Di*rect rix, n.; pl. E. {Directrixes}, L. {Directrices}. 1. A directress. [R.] Jer. Taylor. [1913 Webster] 2. (Geom.) (a) A line along which a point in another line moves, or which in any way governs the motion of the point and determines the… …   The Collaborative International Dictionary of English

• directrix — [də rek′triks; ] also [ dīrek′triks] n. pl. directrixes or directrices [dī΄rek trī′sēz] 1. Rare a woman director 2. Geom. a) a fixed line associated with a conic section and its focus and eccentricity: see PARABOLA b) the curve th …   English World dictionary

• Conic section — Types of conic sections: 1. Parabola 2. Circle and ellipse 3. Hyperbola …   Wikipedia

• Conic section/Proofs — In mathematics, conic sections are relations which represent the equation of the curve (or curves) that result from passing a plane through a cone.CirclesDefinition: The locus of all points in a plane which are equidistant from a given point.… …   Wikipedia

• conic section — Geom. a curve formed by the intersection of a plane with a right circular cone; an ellipse, a circle, a parabola, or a hyperbola. Also called conic. [1655 65] * * * Any two dimensional curve traced by the intersection of a right circular cone… …   Universalium

• directrix — noun (plural directrixes; also directrices) Etymology: Medieval Latin, feminine of Late Latin director, from Latin dirigere Date: 1622 1. archaic directress 2. a fixed curve with which a generatrix maintains a give …   New Collegiate Dictionary

• directrix — noun a) A female who directs; a directress. b) A line used to define a curve or surface; especially a line, the distance from which a point on a conic has a constant ratio to that from the focus …   Wiktionary

• Dandelin spheres — are touching the light blue plane that intersects the cone. In geometry, the Dandelin spheres are one or two spheres that are tangent both to a plane and to a cone that intersects the plane. The intersection of the cone and the plane is a conic… …   Wikipedia

• Cone (geometry) — Not to be confused with the conical surface.. A right circular cone and an oblique circular cone A cone is an n dimensional geometric shape that tapers smoothly from a base (usually flat and circular) to a point called the apex or vertex.… …   Wikipedia

• latus rectum — |lad.əsˈrektəm, |läd. , |lād. noun Etymology: New Latin, literally, straight side : the chord of a conic section through a focus and parallel to a directrix * * * /lay teuhs rek teuhm/, pl. latera recta /lay teuhr euh rek teuh/. Geom. the chord… …   Useful english dictionary

• focus — I. noun (plural foci; also focuses) Etymology: New Latin, from Latin, hearth Date: 1644 1. a. a point at which rays (as of light, heat, or sound) converge or from which they diverge or appear to diverge; specifically the point where the… …   New Collegiate Dictionary