V Due To Infinite Line of Point Charges

[Kajayacht]

Homework Statement

An infinite number of point positive charges of 2.0 C each are arranged in the following linear configuration with a = 88 cm. Find the electric potential at the point 0 on the scale.

(link to image)
http://img232.imageshack.us/i/prob02.gif/

[URL]http://img232.imageshack.us/i/prob02.gif/[/URL]

Homework Equations

Sum of Geometric Series
S = a / (1-r)
Electric Potential
V = k*q / r

The Attempt at a Solution

S = .88 / (1-.5)
S = 1.76 m

V = 8.989e9 * 2 C / 1.76 m
V = 1.021 V which is wrong.

Any ideas what I'm doing wrong?

 

[Kajayacht]

Nevermind, this should be in introductory physics :S Sorry guys lol