# I'll give you 10\$ of my mylot earnings if .......

India
October 7, 2006 7:10am CST
If you can prove 0! = 1 ... thats is ( 0 factorial = 1 .. how ?? ) ... for the brainy ones out here haha
4 responses
@bblessed (1822)
• United States
7 Oct 06
A first way to see that 0! = 1 is by working backward. We know that: 1! = 1 2! = 1!*2 2! = 2 3! = 2!*3 3! = 6 4! = 3!*4 4! = 24 We can turn this around: 4! = 24 3! = 4!/4 3! = 6 2! = 3!/3 2! = 2 1! = 2!/2 1! = 1 0! = 1!/1 0! = 1 In this way a reasonable value for 0! can be found.
1 person likes this
• India
8 Oct 06
great .. u are very smart !! .. u gave me exactly the answer i was expecting .. there isnt any other way of proving it .. anyways i was kidding about the 10\$ haha .. :-) .. dont mind .. bye
• United States
8 Oct 06
well didn't this thread turn out with a fun twist ending.
• India
8 Oct 06
im sure bblessed wasnt expecting 10\$ anyway :-) haha
@register (1065)
• India
2 Dec 07
That is not the exact answer.. Mathematicians defined 0! to be 1. it cannot be proved actually.. 0!=1 needed to be set to make the rest of the peripheral stuff work..Like for eg : x^0 = 1 in order to make the laws of exponents work even when the exponents cannot be thought of as repeated multiplication.
• Italy
31 Dec 07
This is the real exact answer. I may be not good at english since I'm not a native speaker, but I'm Ph.D. in Mathematics, so... the actual definition of factorial is: 0!= 1 (is DEFINED to be) n!= n x(n-1)!(recursively defined by induction for any n 0) If you put it that way, you can observe that all operations and rules for factorials on positive integers are consistent with the definition of 0! = 1. The same is true with the definition of x^0 = 1 because that makes 0 consistent with the rules of division between powers 1 = x^n / x^n = x^(n-n) = x^0
• India
1 Nov 07
dunno!!!
@Maxoo436 (69)