Question

Express n! using product notation.

Answer 1

Hello,

$n!=\prod_{i=1}^n{i}=1*2*3*4...*(n-1)*n$

Answer 2

The factorial of a positive integer $n$, is the product of all positive integers less than or equal to $n$. The factorial of $n$ is written as $n!$.

By definition

$2!=2\times1$

$3!=3\times2\times1$

$4!=4\times3\times2\times1$

Therefore

$n!=n\times(n-1)\times(n-2)\times(n-4)...\times2\times1$

This can rewritten as

$n!=n\times(n-1)!$