# Greens theorem

1. Sep 3, 2008

### dirk_mec1

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

3. The attempt at a solution

I don't know how to choose u. I presume we look in 2D; I thought u should look something like:

$$u = \left[ \begin{array}{c} \psi \\ \psi \end{array} \right]$$

and $$c= \phi$$ but that isn't correct.

2. Sep 3, 2008

### Dick

How about picking two vector fields? Pick u=(psi,0) for the first part and u=(0,psi) for the second part.

3. Sep 4, 2008

### dirk_mec1

Yes of course, thanks Dick!