The Factorial function

What is the Factorial function?

The factorial function is a mathematical formula represented by an exclamation mark "!". In the Factorial formula, you must multiply all the integers and positives that exist between the number that appears in the formula and the number 1.

Here’s an example:

7! = 1 * 2 * 3 * 4 * 5 * 6 * 7 = 5.040

On this formula, number 7 will be called the 7th factorial and multiplied by all the numbers that appear on the example until number 1.

If at this stage you are about to give up I will confess that in your calculator appears a button that will calculate the factorial of the number that you want automatically. You should look for a button similar to "x!" Or "n!".

Examples of factorial formulas

1! = 1 * 1 = 1
3! = 1 * 2 * 3 = 6
10! = 1 * 2 * 3 … 8 * 9 * 10 = 3.628.800

What about the 0 factorial, how to calculate it? If we go back to the definition of factorial function we can see that it does not make sense to apply it in the case of "0". There are no positive numbers before 0 so 0 x 0 = 0.

However, it has been agreed that in the case of 0 factorial the result will be equal to 1:

0! = 0 x 0 = 1