Partial Derivatives Challenge Question

[kingwinner]

http://www.geocities.com/asdfasdf23135/advcal9.JPG

I find this question to be extremely challenging...

The best I can think of is z=f(x,y)=ln(theta), would this work?

Can someone teach me how to define S=domain of f? This problem is giving me bad headaches.

It would be nice if someone can guide me through the solution.

Thanks a million!

 

[kingwinner]

I find it difficult. Anyone willing to take up this challenge?