Spherical Coordinates: Integrating a Hemisphere/Paraboloid

Click For Summary
The discussion revolves around converting a given integral setup from rectangular to spherical coordinates, specifically for a hemisphere or paraboloid. The outer integral ranges from -2 to 2, while the middle and inner integrals define the bounds in the y and z dimensions, respectively. Participants emphasize the importance of visualizing the shape in both 2D and 3D to understand the integration limits better. A key point raised is the relationship between the spherical coordinates ρ and φ, which are not independent due to the nature of the paraboloid. Guidance is sought on how to approach the conversion effectively.
Tater
Messages
9
Reaction score
0
Homework Statement
The outermost integral is:
-2 to 2, dx

The middle integral is:
-sqrt(4-x^2) to sqrt(4-x^2), dy

The inner most integral is:
x^+y^2 to 4, dz






The attempt at a solution

Drawing the dydx in a simple 2d (xy) plane, it is circular with a radius of 2. So this means that the period(theta) will go from 0 to 2pi. Drawing in 3d (xyz) yields a hemisphere/paraboloid. Now this is where I'm stuck. I don't know what to do after this or how to really tackle this problem. Do I want to attempt to draw a 'slice' of it in the spherical outline with the variables phi, rho, theta? Do I have to look at it a certain way (2d or 3d)? I just don't see what I can do!

Any help or guidance is greatly appreciated!
 
Physics news on Phys.org
You haven't actually said what the question asks you to do..
 
Whoops. Thought I stuck that in there. Anyways, all I have to do is convert it to spherical coordinates (from rectangular to spherical).
 
Tater said:
Whoops. Thought I stuck that in there. Anyways, all I have to do is convert it to spherical coordinates (from rectangular to spherical).

I was afraid of that :wink:

It is indeed a paraboloid, so \rho and \phi will not be independent the way they would if it was a spherical section...

Try finding the relationship between \rho and \phi for the paraboloid's curved and flat surfaces
 
From my weblog
http://buyanik.wordpress.com/2009/05/02/laplacian-in-spherical-coordinates/"
 
Last edited by a moderator:
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
9K
  • · Replies 2 ·
Replies
2
Views
2K