In
numerical analysis
Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of numerical methods ...
, Chebyshev nodes are specific
real
Real may refer to:
Currencies
* Brazilian real (R$)
* Central American Republic real
* Mexican real
* Portuguese real
* Spanish real
* Spanish colonial real
Music Albums
* ''Real'' (L'Arc-en-Ciel album) (2000)
* ''Real'' (Bright album) (2010) ...
algebraic numbers, namely the roots of the
Chebyshev polynomials of the first kind. They are often used as nodes in
polynomial interpolation
In numerical analysis, polynomial interpolation is the interpolation of a given data set by the polynomial of lowest possible degree that passes through the points of the dataset.
Given a set of data points (x_0,y_0), \ldots, (x_n,y_n), with no ...
because the resulting interpolation polynomial minimizes the effect of
Runge's phenomenon
In the mathematical field of numerical analysis, Runge's phenomenon () is a problem of oscillation at the edges of an interval that occurs when using polynomial interpolation with polynomials of high degree over a set of equispaced interpolation ...
.
Definition
For a given positive integer ''n'' the Chebyshev nodes in the interval (−1, 1) are
:
These are the roots of the
Chebyshev polynomial of the first kind of degree ''n''. For nodes over an arbitrary interval
'a'', ''b''an
affine transformation can be used:
:
Approximation
The Chebyshev nodes are important in
approximation theory because they form a particularly good set of nodes for
polynomial interpolation
In numerical analysis, polynomial interpolation is the interpolation of a given data set by the polynomial of lowest possible degree that passes through the points of the dataset.
Given a set of data points (x_0,y_0), \ldots, (x_n,y_n), with no ...
. Given a function ƒ on the interval