Thread: Volume Enclosed by surfaces (Triple integration)

Hello! I can't quite get this triple integral problem even after looking at the sticky for integration.

I have the surfaces z = x^2 + 3(y^2) and z = 8 - x*x - y*y and I need to find the volume of the region enclosed.
dV = dzdydx

All help is greatly appreciated!

The integral you want to solve is

The integration area D is given by the equation

EDIT: Fixed notation issues.

I'm confused on why you only have one integral? How do I take this and turn it into three?

It's just a different notation. If it says dxdydz then you obviously have a triple integral.

Just to clarify, my limits are going to be for x: [-2, 2] and for y: [-sqrt(2), sqrt(2)]?
Is that right? or should the y be sqrt(2-x^2 / 2)?

It's easier if you switch to polar coordinates.




Don't forget to scale the new area element:

If you don't want to switch to polar coordinates then you can integrate from and

Ah that makes so much more sense!
Thanks so much!