Question

Dou 20 pontos para quem responder corretamente e com calculo. Simplifique:
$1) \frac{n!}{(n-2)!}$ $1) \frac{(n+1)!}{ (n+2)!} 2) \frac{n!}{(n-2)!}$

Answer 1

     $\frac{n!}{(n-2)!} \\ \\ = \frac{n(n-1)(n-2)!}{(n-2)!} \\ \\ =n(n-1) \\ \\ =n^2-n$


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