I already finished the challenge and understood it fine… My question is:

WHAT IN THE HELL IS THE MATH PART AT THE BOTTOM FOR?? YOU KNOW, THE PART THAT SAYS–>

" return Math.round(Math.pow(Math.sqrt(a) + Math.sqrt(b), 2)); "

**Your code so far**

```
// Setup
function abTest(a, b) {
// Only change code below this line
if (a<0 || b<0){
return undefined
}
// Only change code above this line
return Math.round(Math.pow(Math.sqrt(a) + Math.sqrt(b), 2));
}
// Change values below to test your code
abTest(2,2);
```

**Your browser information:**

Your Browser User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0`

.

**Link to the challenge:**