Simple “Proof” How? Zero Factorial is Equivalent to One
We know that
The general formula of factorial can be written in an entirely prolonged form as
n! = n(n-1)(n-2)(n-3)......3(2)(1)
or in part extended shape as
!&bg=ffffff&fg=000&s=0 "n! = n(n-1)!")
Dividing each side of the equation by,n we have
!+%3D+%5Cfrac%7Bn!%7D%7Bn%7D&bg=ffffff&fg=000&s=0 "(n - 1)! = \frac{n!}{n}")
Using this fact, we can check the following pattern.
(4)(3)(2)(1)%7D%7B5%7D+%3D+24&bg=ffffff&fg=000&s=0 "4! = \displaystyle \frac{5!}{5} = \frac{(5)(4)(3)(2)(1)}{5} = 24")
(3)(2)(1)%7D%7B4%7D+%3D+6&bg=ffffff&fg=000&s=0 "3! = \displaystyle \frac{4!}{4} = \frac{(4)(3)(2)(1)}{4} = 6")
(2)(1)%7D%7B(3)%7D+%3D+2&bg=ffffff&fg=000&s=0 "2! = \displaystyle \frac{3!}{3} = \frac{(3)(2)(1)}{(3)} = 2")
(1)%7D%7B(2)%7D&bg=ffffff&fg=000&s=0 "1! = \displaystyle \frac{2!}{2} = \frac{(2)(1)}{(2)}")
Now, we go to 
