Complete basis Updated 2025-07-16
Finding a complete basis such that each vector solves a given differential equation is the basic method of solving partial differential equation through separation of variables.
The first example of this you must see is solving partial differential equations with the Fourier series.
Notable examples:
- Fourier series for the heat equation as shown at Fourier basis is complete for and solving partial differential equations with the Fourier series
- Hermite functions for the quantum harmonic oscillator
- Legendre polynomials for Laplace's equation in spherical coordinates
- Bessel function for the 2D wave equation on a circular domain in polar coordinates
Harmonic function Updated 2025-07-16
A solution to Laplace's equation.
Helmholtz equation Updated 2025-07-16
eigenvalue problem of Laplace's equation.
Legendre polynomials Updated 2025-07-16
Show up when solving the Laplace's equation on spherical coordinates by separation of variables, which leads to the differential equation shown at: en.wikipedia.org/w/index.php?title=Legendre_polynomials&oldid=1018881414#Definition_via_differential_equation.
Poisson's equation Updated 2025-07-16
Generalization of Laplace's equation where the value is not necessarily 0.
Spherical harmonic Updated 2025-07-16
Correspond to the angular part of Laplace's equation in spherical coordinates after using separation of variables as shown at: en.wikipedia.org/wiki/Spherical_harmonics#Laplace's_spherical_harmonics