Explanation
Radical notation is a way of expressing roots, such as square roots, cube roots, and nth roots. It involves the use of the radical symbol $\sqrt{}$.
For example, the square root of a number $x$ is written as:
$\sqrt{x}$
This can be read as "the square root of $x$" and it represents a number $y$ such that:
$y^2 = x$
For higherorder roots, such as cube roots or fourth roots, an index is added to the radical symbol. The cube root of $x$ would be:
$\sqrt[3]{x}$
This is read as "the cube root of $x$" and represents a number $y$ such that:
$y^3 = x$
In general, the nth root of a number $x$ is expressed as:
$\sqrt[n]{x}$
This signifies a number $y$ such that:
$y^n = x$
Examples

Square Root:
If $x = 16$,
$\sqrt{16} = 4$
because $4^2 = 16$.

Cube Root:
If $x = 27$,
$\sqrt[3]{27} = 3$
because $3^3 = 27$.

Fourth Root:
If $x = 81$,
$\sqrt[4]{81} = 3$
because $3^4 = 81$.
Radical Expressions
Radical notation can also be used with variables and expressions. For instance, if you have an expression $x^2 + 4$, the square root of this expression is:
$\sqrt{x^2 + 4}$
This represents a value that, when squared, gives the expression $x^2 + 4$.
Conversion to Exponential Form
Radicals can also be expressed in terms of exponents. The nth root of $x$ can be written as:
$\sqrt[n]{x} = x^{\frac{1}{n}}$
So,
$\sqrt{x} = x^{\frac{1}{2}}$
$\sqrt[3]{x} = x^{\frac{1}{3}}$
Understanding radical notation is crucial for solving various mathematical problems involving roots and powers.