Square root

Number whose square is a given number

In mathematics, a square root of a number x is a number y such that y 2 = x {\displaystyle y^{2}=x} ; in other words, a number y whose square (the result of multiplying the number by itself, or y ⋅ y {\displaystyle y\cdot y}) is x. For example, 4 and −4 are square roots of 16 because 4 2 = ( − 4) 2 = 16 {\displaystyle 4^{2}=(-4)^{2}=16} . Every nonnegative real number x has a unique nonnegative square root, called the principal square root or simply the square root (with a definite article, see below), which is denoted by x , {\displaystyle {\sqrt {x}},} where the symbol √ is called the radical, among other names, and the line over the number is called the vinculum (sometimes considered a part of the radical symbol itself).

From Wikipedia, under CC BY-SA. More on occurri.