# Divergence theorem

1. Aug 1, 2008

### Tyst

1. The problem statement, all variables and given/known data
Here is a link to the problem:
http://www.brainmass.com/homework-help/physics/electromagnetic-theory/68800

3. The attempt at a solution
To find the divergence

1/r^2*d(r)*(r^2*r^2*cos(theta))
+[1/r*sin(theta)]*d(theta)*(sin(theta)*r^2*cos(phi))
-[1/r*sin(theta)]*d(phi)*(r^2*cos(theta)*sin(phi))

Which gives

1/r^2*4*r^3*cos(theta)
+[1/r*sin(theta)]*(cos(theta)*r^2*cos(phi))
-[1/r*sin(theta)]*(r^2*cos(theta)*cos(phi))

Is this correct?

Last edited by a moderator: Aug 1, 2008
2. Aug 1, 2008

### Defennder

I'm a little confused as to the notational convention for $$\phi \ \mbox{and} \ \theta$$. Which one in this question is the azimuthal angle to the xy plane?

3. Aug 1, 2008

### Tyst

Phi is the azimuthal angle

4. Aug 1, 2008

### Tyst

4rcos(theta) came from simplifying the expressions above it, it is the divergence.

And thank you - you answered my question!