The square root symbol ( ) is used to indicate the quantity or quantities which, when multiplied by itself or themselves, results in the quantity encompassed by the symbol. In engineering applications, the square root is sometimes indicated as the "one-half power," using the fractional exponent 1/2.
Here are two examples of the use of the square root symbol:
In the first instance, the symbol indicates the square root of 4 on the left-hand side, and the two valid resultants on the right-hand side. In the second instance, the expression indicates the square root of the entire quantity ( x + y - z ).
When a square root symbol is used with an expression involving two or more numbers or variables, the quantity affected is indicated by the extent of the horizontal line attached to the surd . The symbol applies only to that quantity underneath the horizontal line.
Also see Mathematical Symbols .