Question

prove that 0!=1 without use permutation and combination

Answer 1

i always thought 0! was defined to = 1

Answer 2

by definition ^ http://mathworld.wolfram.com/Factorial.html it is a special case

Answer 3

We can write (n-1)! as n!/n. We set n - 1 = 0. 0! is then 1!/1 = 1.

Answer 4

remember to close the question :)