Find The Volume; Triple Integrals

In summary, the conversation is about finding the volume of a solid enclosed by two paraboloids in cylindrical coordinates. The boundaries of the solid are 0< r< 1, 0<theta<2pi, and r< z< 32-r. The problem has been solved multiple times, but the answer of 31pi is being questioned. Suggestions are made to take horizontal slices and integrate over z.
  • #1
withthemotive
21
0
Find the volume of the solid enclosed by the paraboloids z = (x^2 + y^2 ) and z = 32 − ( x^2 + y^2) .To make this problem easier to look at I resorting to making it into cylindrical coordinates.
{r, theta, z| 0< r< 1, 0<theta<2pi, r< z< 32-r}

Every time I solve for this I end up getting 31pi and I'm being told it's constantly wrong.
 
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  • #2
Welcome to PF!

withthemotive said:
Find the volume of the solid enclosed by the paraboloids z = (x^2 + y^2 ) and z = 32 − ( x^2 + y^2) .

0< r< 1

Hi withthemotive! Welcome to PF! :smile:

No, r goes from 0 to … ? :wink:

(but isn't it easier just to take horizontal slices of thickness dz, and just integrate once, over z?)
 
  • #3


tiny-tim said:
Hi withthemotive! Welcome to PF! :smile:

No, r goes from 0 to … ? :wink:

(but isn't it easier just to take horizontal slices of thickness dz, and just integrate once, over z?)

LOL...oops.
I was looking at a similar problem on here, I think I might have figured it out now.
 

What is a triple integral?

A triple integral is an integral with three variables, used to calculate the volume of a three-dimensional object or region. It is represented by three nested integrals, with each one representing a different axis.

How do you set up a triple integral?

To set up a triple integral, you need to determine the limits of integration for each variable and the integrand, which represents the function being integrated. The order of integration also needs to be determined, which can be done by using the "right-hand rule" or by visualizing the region in three dimensions.

What is the purpose of using a triple integral?

The purpose of using a triple integral is to calculate the volume of a three-dimensional object or region. It is useful in many fields such as physics, engineering, and mathematics.

What are the applications of triple integrals?

Triple integrals have various applications, including calculating the mass, center of mass, and moment of inertia of a three-dimensional object, determining the probability of a random point falling within a certain region, and finding the volume of irregular shapes or objects.

What are some techniques for solving triple integrals?

Some techniques for solving triple integrals include using symmetry to simplify the integral, using substitution to convert the integrand into a simpler form, and using polar, cylindrical, or spherical coordinates to integrate over curved regions. It is also helpful to break up the region into smaller regions to make the integral more manageable.

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