( testing ... LaTeX )

The probability of getting $k$ heads when flipping $n$ coins is:

$$\sum_{k=0}^{n} {n \choose k} = 2^n$$
$$P(E) = {n \choose k} p^k (1-p)^{ n-k}$$

An Identity of Ramanujan

$$\frac{1}{(\sqrt{\phi \sqrt{5}}-\phi) e^{\frac25 \pi}} = 1+\frac{e^{-2\pi}} {1+\frac{e^{-4\pi}} {1+\frac{e^{-6\pi}} {1+\frac{e^{-8\pi}} {1+\ldots} } } }$$

( ... more later !!! )