Ever think about the sqrt of 1 are 1 and 1?

The mathematical square root of 1 is both 1 and 1, but that's not the only instruction. There's also
Implement int sqrt(int x).
None of the sqrt functions I can think of have returned the negative value as well as the positive, trusting that if you need it, you know that the negative root is 1*positive root, so can obtain it easily, without the hassle of returning multiple numbers or finding which one you want in the list.