User:Mark Durst/sandbox

Trying math: Here's a single variable, $$x$$, written in the middle of a line. And here's something a little more complicated: $$ \sqrt{x+15} +\sqrt{x} = 15 $$ Both seem to work. More complicated LaTeX, not so much.

One more thing to try: $$\lim_{N \to \infty} \sum_{k=1}^N f(t_k) \Delta t$$

A logistic function or logistic curve is a common S-shaped curve (sigmoid curve) with equation


 * $$f(x) = U - \frac{U-L}{1 + e^{-k(x-x_0)}},$$