Happy Pi Day

If you haven't seen =the= classic mathematics movie yet: Pi, do so today. It has a 7/5/10 rating from 76K+ users on IMDB, what more can I add?

Because it's Pi day:

The following proof is simple. = Therefore I provide only the shortest possible and encrypted version of it.

This text is self contained. = The reader is assumed to have a Ph.D. in the field.

Notation. = To disguise the fact that most of this work is copied from the standard text in this subject I have used a different notation.

The last one may seem cynical but the amount of ( literal ) overlap in mathematics books is noteworthy.