Parametre means often a quantity which is considered as constant in a certain situation but which may take different values in other situations; so the parametre is a “variable constant”.  But in giving a curve or a surface in parametric form, the parametres work as proper variables which determine the values of the coordinatesMathworldPlanetmathPlanetmath of the points; then we can describe the parametres as “auxiliary variables”.

The parametric


of the origin-centered circle of parametres:  a (the radius) is a variable constant which is held constant all the time when one considers one circle;  t is an auxiliary variable which has to get all real values (e.g. from the intervalMathworldPlanetmath[0, 2π])  for obtaining all points of the perimetre.

In the analytic geometryMathworldPlanetmath, one speaks of the parametre of parabolaPlanetmathPlanetmath (a.k.a. latus rectum):  it means the chord of the parabola which is perpendicularMathworldPlanetmathPlanetmathPlanetmath to the axis and goes through the focus; it is the quantity 2p in the standard equation   x2=2py  of the parabola (p is the distance of the focus and the directrix).

Title parametre
Canonical name Parametre
Date of creation 2013-03-22 17:06:59
Last modified on 2013-03-22 17:06:59
Owner pahio (2872)
Last modified by pahio (2872)
Numerical id 17
Author pahio (2872)
Entry type Definition
Classification msc 00A05
Synonym parameter
Related topic Indeterminate
Related topic DerivativeForParametricForm
Related topic Curve
Related topic PerimeterOfAstroid
Related topic CissoidOfDiocles
Related topic Variable
Related topic SurfaceNormal
Defines auxiliary variable
Defines parametric form
Defines parametric presentation
Defines parameter of parabola