Unfortunately, JavaScript does not support the square root symbol for function names. Instead, we can use some other Unicode alphabet character to represent a square root function. 

In this example I'll use `ᕂ`. 

Once we have a valid symbol to use, we can use the Math object to generate a square root function. 

<!-- language: lang-javascript -->

 var ᕂ = (function sqrt(_generator_){ return _generator_[arguments.callee.name]; }(Math));
 
 ᕂ(2); // 1.4142135623730951
 ᕂ(100); // 10
 ᕂ(1337); // 36.565010597564445

It's simple! :)

>! Of course, it would be easier to just use `var ᕂ = Math.sqrt;`