Question

Hi. i'm trying to find the exact value of the infinite sum of n(2/3)^n from 1 to infinity. Is this a geometric series?

Answer 1

the first one will be

1*(2/3)^1 = ?

Answer 2

Is this the sum you are looking for?
\[
\sum_{n=1}^\infty n\left(\frac{2}{3}\right)^n
\]