# Curl of field in cylindrical coordinates

1. Sep 17, 2013

### FOIWATER

I am asked to compute the Curl of a vector field in cylindrical coordinates,

I apologize for not being able to type the formula here I do not have that program.

I do not see how the the 1/rho outside the determinant calculation is being carried in?

Not for the specific problem - but for curl in other coordinates in general.

1/rho det(arho rho*bphi cz
d/drho d/dphi d/dz
Arho rho*Atheta Az)

I'm staring at it a long time, - I don't see how it expands as it does..

Any help appreciated.

2. Sep 17, 2013

### rude man

How did you come by a 1/r outside the determinant?

The determinant for computing curl A is

1r/r 1ψ k/r
∂/∂r ∂/∂ψ ∂/∂z
Ar rAψ Az

I used r instead of rho and ψ instead of phi since phi is not available on the PF symbol table.

There is no 1/r term in front of the determinant.

3. Sep 17, 2013

### FOIWATER

There is for cylindrical coordinates

At least in most things I have come across

I am referencing the 5th edition of "elements of electromagnetics"

4. Sep 18, 2013

### rude man

What I gave you and what you said are the same thing. Your version brings 1/r outside the determinant, then multiplies all my terms by r. It's a dumb way of giving the determinant in my opinion, but it's correct also.

What did you say was your problem with it again? I couldn''t figure out what your confusion is.

5. Sep 18, 2013

### FOIWATER

Only the row by which cofactors are expanded, though?

6. Sep 18, 2013

### FOIWATER

nvm I understand it now, thanks