When does this double integral converge?

[windy906]

For the double integral find which values of k make it converge.
\int \int \frac{dA}{(x ^ 2+y^2)^k}

x^2 + y^2 <= 1
I have no idea how to even start going about this, can just about do the basics of multiple integration but not this.

[Office_Shredder]

What is z?

[windy906]

Doesn't say, that is all the information I have.

[Office_Shredder]

Well, is z associated with the integral? Because it really has no bearing on the problem at the moment.... perhaps you meant k?

[windy906]

Yes I did, sorry!
Will edit it now.

[Office_Shredder]

Try converting it to polar coordinates

[windy906]

Thanks, really didn't have a clue what to do.