Question

a) n!
(n-1)!

b) x!
(×-2)!

c) (n+1)
n!

d) (n+2)!
(n-1)! ​

Answer 1

Resposta:

 

 

a)  n! / (n-1)

              = [n(n - 1)(n -2)!] / (n - 1) = n(n -2)!

 

b) X! / (X-2)!

              = X(X - 1)(X - 2)! / (X - 2)! = X(X + 1)

 

c) (n+1) / n(n - 1)(n - 2)!

              = 1 / n(n - 2)!

 

d) X!(X+2)! / (X - 1)!.(X + 1)!

              =  X(X - 1)!.(X +2 )(X + 1)! / ((X - 1)!.(X + 1)! = X(X + 2)

 

e) (N-1)!+(N-2)! / N

              = [(N - 1)(N - 2)! + (N - 2)!] / N = (N - 2)![(N - 1) + 1} / N = (N - 2)!.N / N = (N - 2)!