Possible Duplicate:
How can I evaluate $\sum_{n=1}^\infty \frac{2n}{3^{n+1}}$
I have an infinite series like so:
$\sum_{i=0}^\infty (i+1)x^i$
or basically
$ 1 + 2x + 3x^2 + 4x^3 +... $
Is there a way to simplify this? If so, how?
Possible Duplicate:
How can I evaluate $\sum_{n=1}^\infty \frac{2n}{3^{n+1}}$
I have an infinite series like so:
$\sum_{i=0}^\infty (i+1)x^i$
or basically
$ 1 + 2x + 3x^2 + 4x^3 +... $
Is there a way to simplify this? If so, how?