###### Definition8.2.1The Definition of the Square Root of a Number

If \(y^2=x\) for a positive number \(y\text{,}\) then \(y\) is called the square root of \(x\text{,}\) and we write \(y=\sqrt{x}\text{,}\) where the \(\sqrt{\phantom{x}}\) symbol is called the radical or the root. We call expressions with a root symbol radical expressions. The number inside the radical is called the radicand.