Square Root and Cube Root: In mathematics, the square root of a number x is a number y such that y2 = x; in other words, a number y whose square (the result of multiplying the number by itself, or y ⋅ y) is x. For example, 4 and −4 are square roots of 16 because 42 = (−4)2 = 16. Every non-negative real number x has a unique non-negative square root, called the principal square root, which is denoted by √x, where the symbol √ is called the radical sign or radix. For example, the principal square root of 9 is 3, which is denoted by √9 = 3, because 32 = 3 ⋅ 3 = 9 and 3 is non-negative.
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