# Poisson's Equation in Cylindrical Coordinates

1. Jun 3, 2014

### smileandbehappy

1. The problem statement, all variables and given/known data

2. Relevant equations

Possions Equation and boundary conditions...

3. The attempt at a solution

First Part that I think is right...

However when I try and apply the boundary conditions ie V(a)=V(r)=0... I can't get the answer!

And for the last part I need to use Gauss's Law in integral form. Any help on where I am going wrong?

2. Jun 4, 2014

### rude man

What happened to part (d)? I guess they want you to use your V(r) rather than the easy (Gaussian surface) way.

parts a and b are correct. Nicely done in fact.

In part c you have your A and B as functions of r. They are supposed to be constants. Why don't you solve for A and B using the general solution you derived in (b)? How did you come by the 3rd equation on your second sheet???

(A an aside, you realize you can derive everything using Gauss' law. You should do it to check your Poisson's equation solution.)

3. Jun 5, 2014

### smileandbehappy

Got there in the end... Sort off. I've just submitted this so any help now is more for my understanding rather than me getting a better mark.

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And this part is wrong... Couldn't do it and didn't have time to try and more.

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4. Jun 5, 2014

### rude man

I have a harder time reading these pages than before, but you seem to be on the right track.