Square root  From Wikipedia, the free encyclopedia Jump to:
navigation, search Measured fall time of a small steel sphere
falling from various heights. The data is in good agreement with
the predicted fall time of 2h/g, where h is the height and g is
the acceleration of gravity.  In mathematics, a square root of a
number a is a number y such that y2 = a, in other words, a
number y whose square (the result of multiplying the number by
itself, or y × y) is a.[1] For example, 4 and −4 are square
roots of 16 because 42 = (−4)2 = 16.  Every non-negative real
number a has a unique non-negative square root, called the
principal square root, which is denoted by a, where √ is called
the radical sign or radix. For example, the principal square
root of 9 is 3, denoted 9 = 3, because 32 = 3 × 3 = 9 and 3 is
non-negative. The term whose root is being considered is known
as the radicand. The radicand is the number or expression
underneath the radical sign, in this example 9.      The graph
of the function f(x) = x, made up