# Math Help - evaluate this integral

1. ## evaluate this integral

2. Originally Posted by szpengchao
$\int_{S} \textbf{F}.\textbf{dS} = \int_{V} \text{div}(\textbf{F})\, dV$

Compute divergence of F,

$\int_{V} \text{div}(\textbf{F})\, dV = \int_{0}^1\int_{0}^1\int_{0}^1 \nabla .\textbf{F}\, dx\,dy\,dz$

3. ## i did

what about evaluate this directly ?

what is dS going to be???

4. Originally Posted by szpengchao
what about evaluate this directly ?

what is dS going to be???
dS is the area element. So you need to take that for each face of the cube. It always points outward from the volume.

-Dan