How to expand factorials of the form (n-n')

[khary23]

I know how to expand a factorial of the form (n-2)!. How would one expand (n-n')! ?
Would it just be (n-n')?
thanks in advance

 

[dextercioby]

What do you mean expand ? The factorial is just a <shortening> of a product, so by my records <expanding> it means expressing the whole terms explicitely (if many, maybe use the <...> sign).

 

[khary23]

What I meant is how does one write (n-n')! For example n!= n(n-1)(n-2)...

 

[Mentallic]

n!=(n)(n-1)(n-2)...(2)(1)

Therefore, (n-n')! is just n-n' substituted for all n above, thus

(n-n')(n-n'-1)(n-n'-2)...(2)(1).

 

[khary23]

Ok thought it was that simple. thank you!