I am going on my own through a chapter on functions and here is something that puzzled me in the definition:(adsbygoogle = window.adsbygoogle || []).push({});

Each element in the domain is paired with just one element in the range.

I guess my calculus knowledge interferes, but what about function like f(x) = sqrt(x). It has two roots: + and -. How does set theory account for that? Or is sqrt(x) not a function in set-theoretic terms

Although f(x) = x^2 fits the definition of the function.

Could someone please explain?

Thanks in advance.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Chapter on functions

**Physics Forums | Science Articles, Homework Help, Discussion**