Question

Preciso muito de ajuda urgente Por favor!! _significa Sobre. a) n!_(n-1)! b) (n+2)!_(n-1)! c) (n+1)!+n!_2n!

Answer 1

a)

 

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

 

 

b)

 

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

 

 

c)

 

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