{eli5} What is the Fourier series used for and how does it work?

987 views

Also how such inventions are created or discovered? how can someone come with these ideas?

In: Mathematics

4 Answers

Anonymous 0 Comments

> how can someone come with these ideas?

Fourier’s original motivation came from the study of the [heat equation](https://en.wikipedia.org/wiki/Heat_equation), which models the flow of heat within a material.

This equation is relatively easy to solve in the simple case where the initial heat distribution is a sinusoidal function, but it is not obvious how to solve it for an arbitrary initial condition. However, the heat equation also has the property that it is *linear* – which means that the sum of two solutions of the heat equation is also a solution. Therefore, if you could represent your problem as a sum of simpler problems which you can solve, then you can solve the more complex problem by simply adding them together.

Fourier showed that *any* smooth function could be represented as a (usually infinite) sum of sinusoidal functions, allowing him to solve the heat equation for any initial heat distribution (at least in principle – any actual solution computed this way is only an approximation, because you can’t add up an infinite number of terms, but you can get as close as you need to).

You are viewing 1 out of 4 answers, click here to view all answers.