# 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 $\displaystyle \int e^x \rd x$.