- #1
freshcoast
- 185
- 1
Homework Statement
∞
Ʃ n / 2^n
n=1
Homework Equations
ratio test
lim |a(n+1) / a(n)|
n->∞
The Attempt at a Solution
I have the answer and the steps its just there's one part I am confused on,
first I just apply n+1 to all my n terms, which gives me,
∞
Ʃ [(n+1)/2^(n+1)] / [n/2^n]
n=1
and if I multiply the a(n+1) part by the reciprocal of an, I don't understand how the terms 2^(n+1) and 2^n cancel each other out and leaves me with just a 2?