# Charge Density (rod)

Never mind, i got it, whew

## Homework Statement

http://img137.imageshack.us/img137/6250/chargqg0.th.jpg [Broken]
The rod has a nonuniform charge density lambda = ax (a is a positive constant). Find electric potential at point A.

## Homework Equations

V = kq/r
E = kqq/r^2
V = -$$$\int_a^b E dot dr$$$

## The Attempt at a Solution

I am pretty close to the answer, I'm just not quite there.
If I'm not mistaken it is something like:
$$\[ \int_d^{L+d} kax*r/r^2\,dr$$
but I'm not quite sure what to do with the 'x', from the answer, I know that it has to end up being the integral of 1/r, so x can't be r because it would end up being just the integral of dr

Maybe the limits are incorrect?

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