# ProofWiki:Jokes/Sex is Fun

## Joke

Let $e^{x / n} = \dfrac \d {\d x} \map f u$.

Then:

\(\displaystyle \sqrt [n] {e^x} =\) | \(=\) | \(\displaystyle \dfrac \d {\d x} \map f u\) | |||||||||||

\(\displaystyle \leadsto \ \ \) | \(\displaystyle \paren {\sqrt [n] {e^x} }^n\) | \(=\) | \(\displaystyle \paren {\dfrac \d {\d x} \map f u}^n\) | ||||||||||

\(\displaystyle \leadsto \ \ \) | \(\displaystyle e^x\) | \(=\) | \(\displaystyle \paren {\dfrac \d {\d x} \map f u}^n\) | ||||||||||

\(\displaystyle \leadsto \ \ \) | \(\displaystyle \int e^x\) | \(=\) | \(\displaystyle \int \paren {\dfrac \d {\d x} \map f u}^n\) | ||||||||||

\(\displaystyle \leadsto \ \ \) | \(\displaystyle \int e^x\) | \(=\) | \(\displaystyle \map f u^n\) |

Purists are entitled of course to quibble that the left hand side should really read $\displaystyle \int e^x \rd x$.