Orthogonal functions: Difference between revisions

Revision as of 23:26, 5 August 2016

Revision as of 23:34, 5 August 2016

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==Trigonometric functions==

{{Main article|Fourier series|Harmonic analysis}}

Several sets of orthogonal functions have become standard bases for approximating functions. For example, the sine functions, sin ''nx'', are orthogonal on the interval (-π, π), if ''m'' ≠ ''n''. For then

:<math>2 \sin mx \sin nx = \cos (m - n)x - cos (m+n) x, </math>

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==See also==

* [[Hilbert space]]

* [[Harmonic analysis]]

* [[Eigenvalues and eigenvectors]]

* [[Wannier function]]