TeX Quellcode:

\begin{array}{rcl} e^{ix} &=& e^{\frac{2\pi ix}{2\pi}} \\ &=& e^{2\pi i \cdot \frac{x}{2\pi}} \\ &=& (e^{2\pi i})^{\frac{x}{2\pi}} \\ &=&1^{\frac{x}{2\pi}} \\ &=& 1\end{array}