# Divergence in cylindrical coordinate system

1. Oct 14, 2007

### Sesse

I am trying to understand the derivation of the divergence formula in cylindrical coordinates. This paper does a good job of explaining it but I don't understand 2 things that the author does.
$$\frac{\partial\hat{\rho}}{\partial\phi} = \hat{\phi}$$ and $$\frac{\partial\hat{\phi}}{\partial\phi} = \hat{\rho}$$
Derivation is on page 3.
Can anyone help me understand this?

2. Oct 14, 2007

### quasar987

go back to page 1: "derivation of unit vectors with the coordinates"

3. Sep 5, 2010

### raj2check

As note below, one finds z^ etc (unit vector), in variation vectors does the differentiation with respect to $$\rho$$,$$\phi$$, z

OK
Now my question is how do you find

$$\overline{}$$$$\rho$$ (line above, could not get that to work)= x $$\widehat{}$$x+ y $$\widehat {}$$y

4. Sep 5, 2010

### raj2check

that one is found in page 1 of the link