The Exponential Function

$$\begin{eqnarray*} \mrr {e^x}{\isdef }{\displaystyle\lim_{n\to\infty}\left(1+\fra... ...{-j\theta}}{2}} \mrr {e}{=}{2.7\,1828\,1828\,4590\,\ldots}{}{}{} \end{eqnarray*}$$