Question

Resolva as equações a) An,2= 56 b) An,3= 8.An,2

Answer 1

Boa noite Rebecca

a)

A(n,2) = n!/(n - 2)! = 56 

n*(n - 1)*(n - 2)!/(n - 2)! = 56 

n² - n - 56 = 0 

delta
d² = 1 + 224 = 225
d = 15

n = (1 + 15)/2 = 8 

b)

A(n,3) = 8*A(n,2) 

n!/(n - 3)! = 8*n!/(n - 2)! 

(n - 2)!/(n - 3)! = 8 

(n - 2)*(n - 3)!/(n - 3)! = 8

n - 2 = 8

n = 10