Why does 0!=1 Why does i happen?

[contactskn 2]

man...is this a homework assignment or somethin'? the answer can be found here.... http://mathforum.org/dr.math/faq/faq.0factorial.html

from your example, it explains to work backwards, not forwards so when working backwords, you have to divide, not multiply.

you already defined 4!=24 , 3!=6 , 2! = 2 and 1! = 1

going backwards, you will see that 3!=4!(24 remember)/4 =6 , 2!=3!(6 remember)/3=2 , 1!=2!/2=1

so what do you think 0! is now? well, 0! would equal 1!/1. since 1!=1, 1/1 is 1 and that is what 0! equals. ONE!

Thank U dear friend to give such a good link and piece of information. It was really informative and knowledgable. 

[Lightning73 0]

I also thought it was a programming question or whatever lol. Anyway, now I know what factorial is, and I also read the answer here. So thanks for both of them

[Nabb 0]

I also saw the title as "Why does 0 != 1" rather than "Why does 0! = 1". Spacing could make it a bit clearer.The alternative way to see reasoning behind this (not the work backwards way) is to use the probability definition of factorial - n! is the number of ways you can order n items. 0! is the number of ways you can order 0 items, which is 1.

[kobra500 1]

You all took ages saying "I don't know why", A link that was given it the first post explained it clearly, CLICK LINKS!!!Are you taking a level maths ? I'm asking because we're doing them at the moment.

Edited December 7, 2008 by kobra500 (see edit history)

[iGuest 3]

a factorial is number that mulply, ex, 4!=4*3*2*1=24