Source: /cirosantilli/wave-equation-solution-with-fourier-series

= Wave equation solution with Fourier series
{tag=Solving partial differential equations with the Fourier series}

https://web.archive.org/web/20200621205928/https://courses.maths.ox.ac.uk/node/view_material/1720 also mentioned at https://math.stackexchange.com/questions/579453/real-world-application-of-fourier-series/3729366\#3729366 from <heat equation solution with Fourier series>.