Difference between revisions of "Chebyshev U"

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=Properties=
 
=Properties=
 
<div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
 
<div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
<strong>Theorem (Orthogonality):</strong> The following formulas hold:
+
<strong>Theorem:</strong> The following formula holds:
$$\int_{-1}^1 \dfrac{T_m(x)T_n(x)}{\sqrt{1-x^2}} dx = \left\{ \begin{array}{ll}
 
0 &; m \neq n \\
 
\dfrac{\pi}{2} &; m=n\neq 0 \\
 
\pi &; m=n=0
 
\end{array} \right.$$
 
and
 
 
$$\int_{-1}^1 \dfrac{U_m(x)U_n(x)}{\sqrt{1-x^2}} dx = \left\{ \begin{array}{ll}
 
$$\int_{-1}^1 \dfrac{U_m(x)U_n(x)}{\sqrt{1-x^2}} dx = \left\{ \begin{array}{ll}
 
0 &; m \neq n \\
 
0 &; m \neq n \\

Revision as of 10:35, 23 March 2015

The Chebyshev polynomials of the second kind are orthogonal polynomials defined by $$U_n(x) = \sin(n \mathrm{arcsin}(x)).$$

Properties

Theorem: The following formula holds: $$\int_{-1}^1 \dfrac{U_m(x)U_n(x)}{\sqrt{1-x^2}} dx = \left\{ \begin{array}{ll} 0 &; m \neq n \\ \dfrac{\pi}{2} &; m=n\neq 0\\ 0 &; m=n=0. \end{array} \right.$$

Proof: