User:El pak/sandbox

"Rough Paper" for me to scribble things up
$$\frac{1}{n}$$ <-->  \frac{1}{n}

$$\sum_{j=0}^{n-1}$$ <-->  \sum_{j=0}^{n-1}

$$e^{\frac{2\pi i}{n} j k}$$ <-->  e^{\frac{2\pi i}{n} j k}