Question

42. Вычислить ((n+2)!)/n!
A) n^2+3n+2
B) n
C) n+2
D) n+1
E) 1

Answer 1

$frac{(n+2)!}{n!} = frac{(n+2)*(n+1)*n!}{n!}=(n+2)*(n+1)=n^2+3n+2. A)$