Square Root

A square root of a number x is a number y such that y squared equals x, making it the inverse of squaring; for example, both 4 and negative 4 are square roots of 16, since 4 squared and negative 4 squared both equal 16. Every non-negative real number has a unique non-negative square root, called its principal square root and written with the radical symbol, so that the principal square root of 9 is 3. Every positive number in fact has two square roots, one positive and one negative, though the phrase the square root is often used loosely to mean the principal one. The concept extends beyond the real numbers into the complex numbers, which makes it possible to meaningfully define square roots of negative numbers as well. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/