Square roots are always nonnegative
![\[Square roots are always nonnegative\]](http://latex.artofproblemsolving.com/a/a/0/aa0763fb1006fcc68067567b3bec3bddcacb04f1.png)
Many people around the world get confused, thinking that 
and 
are the same. Though both of these are similar, one of them only has one answer. If we take , we can see that it has 
answers; 
and 
. On the other hand, 
only has one.
Square Root is a function, and a function cannot have two different answers for one input. Technically and are "square roots" of 
, but the square root function only represents one of them--the nonnegative answer.
