- #1
billiards
- 767
- 16
I am stuck on this problem.
Use these equations:
[tex]\textbf{v}(\textbf{r}) = f(r)\textbf{r}[/tex]
[tex]\frac{\partial r}{\partial x} = \frac{x}{r}[/tex]
And the chain rule for differentiation, show that:
[tex](\nabla\cdot\textbf{v}) = 2f(r) + r\frac{df}{dr}[/tex]
(cylindrical coordinates)
Any help greatly appreciated, I will post my progres so far in a following post.
Cheers
Use these equations:
[tex]\textbf{v}(\textbf{r}) = f(r)\textbf{r}[/tex]
[tex]\frac{\partial r}{\partial x} = \frac{x}{r}[/tex]
And the chain rule for differentiation, show that:
[tex](\nabla\cdot\textbf{v}) = 2f(r) + r\frac{df}{dr}[/tex]
(cylindrical coordinates)
Any help greatly appreciated, I will post my progres so far in a following post.
Cheers