# Homework Help: Double integral to find volume of a solid

1. Dec 8, 2013

### mikky05v

The problem statement, all variables and given/known data
Set up a double integral to find the volume of the solid bounded by the graphs y=4-x2 and z=4-x2

The attempt at a solution

I drew myself a 3d graph but it's just a parabloid in the xy plane and a parabloid in the xz plane right? so I'm unsure how to set up my integral. This was my attempt, my thought was that perhaps z=4-x2 could be considered like the surface

$\int$20$\int$4-x20 (4-x2) dy dx

Could some one give me some input?

2. Dec 8, 2013

### LCKurtz

What you have done looks reasonable, but isn't there more detail about the region in question? Like first octant or y positive or something?? Otherwise the volume isn't bounded. Can't tell if your answer is correct without knowing more.

3. Dec 8, 2013

### mikky05v

oh yes sorry first octant is what it says. I wasn't entirely sure what that meant but I assumed it meant only the positive section of the 3d graph

4. Dec 8, 2013

### LCKurtz

The first octant is where all three variables are positive. If that's your region your integral is set up correctly.