Question

0! = 0
Is this true or false? And what does the "!" mean?

Answer 1

The statement A! is true if and only if A is false

Answer 2

?

Answer 3

"!" is the symbol for a factorial

factorials are defined like this
\[n! = n * (n-1) * (n-2) * ... *1\]
where n is a positive number.

you can think of factorials as the number of permutations of numbers from 1 to n, EX

2! = 2 * 1 = 2
so how many ways can you write {1, 2} ?
{1, 2} , {2, 1} , so 2 ways

1! = 1
{1}, 1 way

0! is tricky, you need to get into sets, but there is a thing called a null set, a set that contains nothing {}, and you can write this 1 way

therefore, 0! = 1

Answer 4

another example of a factorial, 6! = 6 * 5 * 4 * 3 * 2 * 1,
7! = 7 * 6 * 5 * 4 * 3 * 2 * 1

Answer 5

Ohh ok, thanks :)