Triple integral finding bounds?

In summary, the problem is to integrate a function over a solid defined by a cone centered at the positive z-axis with vertex at the origin, a sphere centered at the origin, and two planes perpendicular to the x-y plane. The given points P, Q, and R act as reference points for determining the bounds of integration. The x, y, and z bounds are determined by dividing the solid into horizontal slices and integrating over z.
  • #1
beallio
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Homework Statement



Integrate the function over the solid given by the figure below (the bounding shapes are planes perpendicular to the x-y plane, a cone centered about the positive z-axis with vertex at the origin, and a sphere centered at the origin), if P=(0,0,5),Q=(0,4,3), and R=(sqrt(6),sqrt(10),0) .



https://instruct.math.lsa.umich.edu/webwork2_course_files/ma215-f08/tmp/gif/homework8b-prob1-pimages/sfig16-8-1g4.gif


Homework Equations





The Attempt at a Solution


planes perpendicular to the x-y plane are the x-z plane and the y-z plane

how do you use the figure to get the bounds for x,y,z

I think that x is from 0 to R
then y is from 0 to 4
and z is from 0 to 5

is this correct? do I need to switch to spirical coordinates?
 
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  • #2
Welcome to PF!

beallio said:
Integrate the function over the solid given by the figure below (the bounding shapes are planes perpendicular to the x-y plane, a cone centered about the positive z-axis with vertex at the origin, and a sphere centered at the origin), if P=(0,0,5),Q=(0,4,3), and R=(sqrt(6),sqrt(10),0) .

planes perpendicular to the x-y plane are the x-z plane and the y-z plane

how do you use the figure to get the bounds for x,y,z

I think that x is from 0 to R
then y is from 0 to 4
and z is from 0 to 5

Hi beallio! Welcome to PF! :smile:

No, "planes perpendicular to the x-y plane" means the y-z plane and the vertical plane through R.

The top surface is part of a sphere, and the "front surface" is also curved … it's the cone through Q.

Hint: divide the solid into horizontal slices of thickness dz, and integrate over z (split the integration into two parts … one below Q, and one above Q, since they'll be different functions). :wink:
 

Related to Triple integral finding bounds?

1. What is a triple integral?

A triple integral is an extension of a basic integral in calculus that involves three variables instead of just one. It is used to calculate the volume of a three-dimensional shape or the mass, moment of inertia, or other physical quantities that are spread out over a three-dimensional region.

2. What are the steps for finding the bounds in a triple integral?

The first step is to visualize the three-dimensional region and determine the type of coordinates (Cartesian, cylindrical, or spherical) that will be used. Then, the bounds for each variable must be identified by looking at the boundaries of the region in each coordinate plane. Finally, the bounds are written in terms of the chosen coordinate system and the triple integral is set up accordingly.

3. How do I choose the appropriate coordinate system for a triple integral?

The choice of coordinate system depends on the symmetry of the region. If the region has cylindrical or spherical symmetry, then it is more convenient to use cylindrical or spherical coordinates, respectively. If the region does not have any symmetry, then Cartesian coordinates are usually the best choice.

4. What are the common mistakes when finding the bounds in a triple integral?

One common mistake is forgetting to account for the boundaries of the region in all three coordinate planes. Another mistake is to confuse the order of the variables, which can lead to incorrect bounds and therefore, an incorrect integral. It is also important to check for any overlapping regions that must be subtracted from the total volume.

5. Can I use a calculator or software to find the bounds in a triple integral?

Yes, there are many online calculators and software programs that can help with finding the bounds in a triple integral. However, it is important to understand the concept and steps behind finding the bounds in order to use these tools effectively and avoid potential errors.

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