Find the mass of the cylinder , if the density at the point is .
I think we should use the cylincal polar method to do this, however i have problem converting this into the polar form, which is , ,
No, I don't think you've quite got it yet. Just plugging in gives:
You see how I work here: step-by-step. I don't often skip steps.
The other thing you have to worry about is that the volume differential in cylindrical components is not just
So, putting this all together, what does your integral look like now?