Volume in spherical coordinates

Click For Summary

Homework Help Overview

The discussion revolves around calculating the volume of a solid region defined by the equation z = √(x² + y²) and bounded by the planes z = 1 and z = 2, within the context of spherical coordinates.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the visualization of the solid and discuss integrating over specified bounds. Questions arise regarding the appropriate limits for integrals in spherical coordinates, and some suggest using cylindrical coordinates instead.

Discussion Status

Participants are actively discussing different methods to approach the problem, including the use of spherical and cylindrical coordinates. There is a recognition of the need to visualize the solid to better understand the volume, and some guidance has been offered regarding plotting and setting limits for integration.

Contextual Notes

There are mentions of specific limits for integration based on the geometry of the solid, as well as the suggestion to plot the region to clarify the volume's shape. The discussion reflects varying interpretations of the best coordinate system to use for the problem.

rc3232
Messages
1
Reaction score
0

Homework Statement


Calculate volume of the solid region bounded by z = √(x^2 + Y^2) and the planes z = 1 and z =2


Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
Edit: You could visualize it and integrate over 1 and add these volumes.
 
Last edited:
it's a cone, but how do you set the limits for the different integrals in spherical coordinates?
 
In sphereical coordinates you know that [itex]x=\rho\cos\theta\sin\phi[/itex], [itex]y=\rho\sin\theta\sin\phi[/itex] and [itex]z=\rho\cos\phi[/itex]
You can use this to find limits for [itex]\rho[/itex].
If you draw the x-z or y-z plane intercept this can help you find [itex]\phi[/itex]
 
You should first plot it to know what the volume looks like.

The volume between z=1 and z=2 is that of a circular disk. You need to use cylindrical coordinates.

Description of the region:
For r and θ fixed, z varies from z=1 to z=2
For θ fixed, r varies from r=1 to r=√2
θ varies from θ=0 to θ=2∏

Plug the limits into the triple integral and evaluate to find the required volume:
[tex]\int \int \int dr d\theta dz[/tex]
 

Attachments

  • graph.gif
    graph.gif
    12.5 KB · Views: 529

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
4
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K