“Meh.”

The **Principle of Least Action** is a variational principle that explains why Mathematics students do as little work as possible. It was the culmination of a few minutes of work by the Pierre de Fermat, although he could not be bothered to write it down. The Principle of Least Action can be derived from Newton's fourth law and applying the definion of a Cambridge Mathmo.

It is usually defined by the path integral:

**Glossary of mathematical terms**