Back in October I published two posts involving the ubiquitous **exponential function**. [see: *Circular Math* and *Fourier Geometry*] The posts were primarily about Fourier transforms, but the exponential function is a key aspect of how they work.

We write it as ** e^{x}** or as

**(**

*exp***) — those are equivalent forms. The latter has a formal definition that allows for the complex numbers necessary in physics. That definition is of a**

*x**series*that converges on an answer of increasing accuracy.

As a sidebar, I thought I’d illustrate that convergence. There’s an interesting non-linear aspect to it.