Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$\text{radicand: } \dfrac{x}{y+4} \\\text{index: } 5$
The radicand and the index of the given expression, $x^2y^3\sqrt[5]{\dfrac{x}{y+4}} ,$ are \begin{array}{l} \text{radicand: } \dfrac{x}{y+4} \\\text{index: } 5 .\end{array} In the expression $\sqrt[y] x$, y is the index while x is the radicand.