flux of vector field

[-EquinoX-]

1. The problem statement, all variables and given/known data

http://img16.imageshack.us/img16/9926/fluxs.th.jpg (http://img16.imageshack.us/my.php?image=fluxs.jpg)


2. Relevant equations



3. The attempt at a solution

I really don't know how to solve this, can anyone help me please?

[lanedance]

try starting with the definition of flux