Math Help - Divergence answer check.

Hi,

I'd just like someone to verify my answer to the following:

My answer (after much working out and simplifying):

$
\nabla \cdot F = \frac{3}{\sqrt{x^2+y^2+z^2}}-\frac{x^2-y^2-z^2}{(x^2+y^2+z^2)^{3/2}}
$

2. Originally Posted by scorpion007
Hi,

I'd just like someone to verify my answer to the following:

My answer (after much working out and simplifying):

$
\nabla \cdot F = \frac{3}{\sqrt{x^2+y^2+z^2}}-\frac{x^2-y^2-z^2}{(x^2+y^2+z^2)^{3/2}}
$
I think there's some sign problems. Here's what I got

$
\nabla \cdot F = \frac{3}{\sqrt{x^2+y^2+z^2}}-\frac{x^2+y^2+z^2}{(x^2+y^2+z^2)^{3/2}} = \frac{2}{\sqrt{x^2+y^2+z^2}}
$

3. Ah, thanks. I knew I messed up the signs in the last bit.