Why 0 factorial equal to 1

you can see the factorial as many different ways, i will only show you two

you can see  

so 0! would mean that

the other way you can see factorial is as the number of ways to order n things

let's say we have

a   b and c and we want to arrange them in all possible ways so those are

abc

acb

bac

bca

cab

cba

and no more

for just a and b

we have

ab

ba

and no more

for just a

we have only

a

for no objects we have

that way, the one that it's upward, it's a bit philosophical but i hope you understand it

what is the question because that is not a question.

electrical power