#1**+5 **

The term is "factorial".....it represents the product of the first "n" positive integers and is written as n!

Thus,

3! = The product of the first three positive integers = 3*2*1 = 6

And 5! = The product of the first five positive integers = 5*4*3*2*1 = 120

This idea is used quite frequently in the areas of probability and statistics to count sets or orderings of things.

------------------------------------------------------------------------------------------------------

Proof that...... (0! = 1).......while not a "formal" proof, here's the idea........

3! = 3*2*1

2! = 2*1 = (3*2*1)/3 = 3!/3

1! = (2*1)/2 = 2!/2

Then.....

0! = 1!/1 = 1

CPhill
Jun 3, 2014

#1**+5 **

Best Answer

The term is "factorial".....it represents the product of the first "n" positive integers and is written as n!

Thus,

3! = The product of the first three positive integers = 3*2*1 = 6

And 5! = The product of the first five positive integers = 5*4*3*2*1 = 120

This idea is used quite frequently in the areas of probability and statistics to count sets or orderings of things.

------------------------------------------------------------------------------------------------------

Proof that...... (0! = 1).......while not a "formal" proof, here's the idea........

3! = 3*2*1

2! = 2*1 = (3*2*1)/3 = 3!/3

1! = (2*1)/2 = 2!/2

Then.....

0! = 1!/1 = 1

CPhill
Jun 3, 2014