210 Real Parameter

A real parameter is a real number variable that is used to define a family of functions. It is used to select a specific member from a set.

Note: Also called parameter. Also described as a real number constant in the same role.

definition [d] (Real Parameter = Parameter) From do Carmo: a parametrized differentiable curve is a differentiable map

  • \(\boldsymbol{\alpha}: I \rightarrow \mathbb{R}^{3}\)

of an open interval \(I = (a,b)\) of the real line \(\mathbb{R}\) into \(\mathbb{R}^{3}\). Differentiable means that each \(t \in I\) is mapped to a point

  • \(\boldsymbol{\alpha}(t) = \bigl(x(t),\, y(t),\, z(t)\bigr)\)

in such a way that the functions \(x(t)\), \(y(t)\), \(z(t)\) are differentiable. The variable \(t\) is called the parameter of the curve.

where

  • \(t\) is the real parameter.
  • \(I = (a,b)\) is an open interval of \(\mathbb{R}\).
  • \(\boldsymbol{\alpha}\) is the parametrized differentiable curve.
  • \(x(t)\), \(y(t)\), \(z(t)\) are differentiable real-valued functions.

210.1 References

  1. do Carmo, M. P. Differential Geometry of Curves and Surfaces. β€” parametrized differentiable curve \(\boldsymbol{\alpha}: I \to \mathbb{R}^{3}\); β€œThe variable \(t\) is called the parameter of the curve.”