# Urgent help! Vector Calculus question

1. Nov 21, 2008

### lembeh

Urgent help! Vector Calculus question....

Let S be the surface given by the graph z = 4 - x2 - y2 above the xy-plane (that it is, where z $$\geq$$ 0) with downward pointing normal, and let

F (x,y,z) = xcosz i - ycosz j + (x2 + y2 ) k

Compute $$\oint$$$$\oint$$sF dS. (F has a downward pointing normal)

(Hint: Its easy to see that div F = 0 on all R3. This implies that there exists a vector field G such that F = Curl G, although it doesnt tell you what G is)

Last edited: Nov 21, 2008
2. Nov 21, 2008

### lembeh

Re: Urgent help! Vector Calculus question....

Please help me with this. Ive been working on it for 6 hours now and still cant figure it out.....Your help is really appreciated!

3. Nov 22, 2008

### PhysicalAnomaly

Re: Urgent help! Vector Calculus question....

I was about to suggest something but apparently, you have to show some attempts before we can help you.