Which of these sequences whose nth term is given below is increasing? (5 points)
A) a sub n = 1/n
B) a sub n = 3/n cubed
C) a sub n = n/n + 2
D) a sub n = 2^n/ (n plus 1)!
I got B. Please check!
2 answers
Is this right?
not B
Take a look at C.
The ratio a_n+1 / a_n is
(n+1)/(n+3) / (n/(n+2)
(n+1)/(n+3) * (n+2)/n
= (n^2+3n+2)/(n^2+3n)
> 1
so the terms are increasing. They converge to 1.
Take a look at C.
The ratio a_n+1 / a_n is
(n+1)/(n+3) / (n/(n+2)
(n+1)/(n+3) * (n+2)/n
= (n^2+3n+2)/(n^2+3n)
> 1
so the terms are increasing. They converge to 1.