Arithmetical root. Algebraic root.
Absolute value (modulus) of number.
As we know, an even degree root has two values: positive and negative, so
An arithmetical root of the n-th degree of a non-negative number a is called a non-negative number, the n-th power of which is equal to a .
An algebraic root of the n-th degree of a given number a iscalled a set of all roots of this number. An algebraic root of an even degree has the two values:positive and negative, for instance:
An algebraic root of an odd degrees has a single value: either positive, or negative.For example, the arithmetical root
Unlike this, the cube degree root:
An arithmetical root is closely connected with the notion of an absolute value(modulus) of number, exactly:
Operations with roots in more detail see the section “Powers and roots”.