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
Nth root real. Finally, if "x" is not real, then none of its "n"th roots is real. Roots are usually written using the radical symbol or "radix" with formula_2 denoting the principal square root of formula_3, formula_4 denoting the principal cube root, formula_5 denoting the principal fourth root, and so on. In the expression formula_6, "n" is called the "index", formula_7 is the "radical sign" or "radix", and formula_3 is called the "radicand". Since the radical symbol denotes a function, it is defined to return only one result for a given argument formula_3, which is called the principal "n"th root of formula_3.