The nth root of a real numbera expresses another real number that, when multiplied by itself n times, will result in a. In addition to the radical symbol, the notation is made up of the radicanda and the indexn.
The resulting number is commonly called a radical. For example, the radical expression 416 is the fourth root of 16. Notice that 416 simplifies to 2 because 2 multiplied by itself 4 times equals 16.
The general expression na represents a number which equals a when multiplied by itself n times.
For any real numbera and natural numbern, the expression an1 is defined as the nth root of a. Note that a root with an even index is defined only for non-negative numbers. Therefore, if n is even, then a must be non-negative.