Menu

The Factorial Function

Primary tabs

Lesson Summary:

The Factorial Function is denoted by

$n!$ and means we multiply the numbers

$1$ through

$n$ together.

Lesson Inputs:

Lesson Outputs:

Lesson:

The Factorial Function is a function of positive integers that is denoted by $n!$ and means we multiply the numbers $1$ through $n$ together. So

For example,

Furthermore, we define the

$0!$ as being equal to

$1$ . And just so we are clear,

$1!=1$ .

Notice that

and

Finally, the language we use is to say "factorial." For example, when referring to $5!$ we would say "five factorial."