Question

Could any1 explain me how \[(n+2)!\] is equal to \[(n+2)(n+1)n!\]?

Answer 1

Like 5!=5(5-1)!=5(5-1)(5-2)!=5(4)(3!)
You know n!=n(n-1)!
So it is (n+2)!=(n+2)(n+2-1)!
=(n+2)(n+1)!
I similar way (n+1)!=(n+1)n!
So (n+2)!=(n+2)(n+1)n!

Answer 2

Thanks :)