Thread:John Lee Gamma Guild Team Vi Hart/@comment-25079450-20150906050807/@comment-24808864-20150908042024

John Lee Gamma Guild Team Vi Hart wrote: sqrt(9)=x

What is x? The answer here will be x=81.

To clarif y previous comments in this string, for sqrt(x) to be well-defined as a function it is necessary that each input have at most one output.

The sqrt(x) function is thus defined to yield the principal square root, the positive square root (well, except for zero I guess)!

On the other hand, when solving equations, it is possible to have multiple solutions. Therefore x^2=9 would have two possible solutions, namely x=3 or -3.