ABSTRACT
The theory of Fourier series discussed in the preceding chapter had its historical origin in the middle of the eighteenth century, when several mathematicians were studying the vibrations of stretched strings. The mathematical theory of these vibrations amounts to the problem of solving the partial differential equation () a 2 ∂ 2 y ∂ x 2 = ∂ 2 y ∂ t 2 , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315371825/895247ed-bf4c-467d-b370-ced59759b8c3/content/eq1520.tif"/>
