Nth root Nth root In mathematics, an "n"th root of a number "x", where "n" is usually assumed to be a positive integer, is a number "r" which, when raised to the power "n" yields "x": where "n" is the "degree" of the root. A root of degree 2 is called a "square root" and a root of degree 3, a "cube root". Roots of higher degree are referred by using ordinal numbers, as in "fourth root", "twentieth root", etc. For example: Any non-zero number, considered as complex number, has "n" different "complex roots of degree "n"" ("n"th roots), including those with
Cube root of a number "x" are the numbers "y" which satisfy the equation For any real number "x", there is "one" real number "y" such that "y" = "x". The cube function is increasing, so does not give the same result for two different inputs, plus it covers all real numbers. In other words, it is a bijection, or one-to-one. Then we can define an inverse function that is also one-to-one. For real numbers, we can define a unique cube root of all real numbers. If this definition is used, the cube root of a negative number is a negative number.