Question

DAU COROANA!!!

Sa se aduca la o forma mai simpla: (n+1)!n! / (n-1)!(n+2)!

Answer 1

n! supra (n+1)!(n-1)!(n+2)! din care eliminam n-1 si n+1 si ramane n! supra (n+2)!

Answer 2

$\dfrac{(n+1)!n!}{(n-1)!(n+2)!}= \\ \\ = \dfrac{(n+1)!(n-1)!n}{(n-1)!(n+1)!(n+2)} = \\ \\ = \dfrac{n}{n+2}$