How Do You Calculate the Normal Vector of a Sphere in Spherical Coordinates?

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    Normal Sphere Vector
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Discussion Overview

The discussion revolves around calculating the normal vector of a sphere defined by the equation V = x² + y² + z² ≤ 1, particularly in spherical coordinates. Participants explore methods for finding the normal vector and its relation to the divergence theorem of Gauss.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant presents the conversion of the sphere's equation to spherical coordinates, expressing uncertainty about the next steps in calculating the normal vector.
  • Another participant suggests using the gradient of the surface function f(x,y,z)=0 to find the normal vector.
  • A different participant indicates a specific interest in proving the divergence theorem of Gauss, which may influence the method used to find the normal vector.
  • There is a suggestion that the same method of finding the normal vector applies in polar coordinates, requiring the gradient in that coordinate system instead of Cartesian coordinates.

Areas of Agreement / Disagreement

Participants express differing approaches to the problem, with some focusing on the gradient method while others emphasize the context of the divergence theorem. No consensus is reached on a specific method or approach.

Contextual Notes

Participants do not clarify certain assumptions regarding the coordinate transformations or the implications of the divergence theorem on their calculations. The discussion lacks resolution on the best method to apply.

brunette15
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I am given the sphere V= x^2 + y^2 + z^2 =< 1

I have converted it to spherical coordinates:

x = rsin(t)cos(f)
y = rsin(t)cos(f)
z = rcos(t)

where t ranges from 0 to pi, and f ranges from 0 to 2pi.

I am unsure how to go about this problem from here. Any guidance would be really appreciated :)
 
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brunette15 said:
I am given the sphere V= x^2 + y^2 + z^2 =< 1

I have converted it to spherical coordinates:

x = rsin(t)cos(f)
y = rsin(t)cos(f)
z = rcos(t)

where t ranges from 0 to pi, and f ranges from 0 to 2pi.

I am unsure how to go about this problem from here. Any guidance would be really appreciated :)

Hey brunette15! ;)

We can find the normal of a surface $f(x,y,z)=0$ by taking the gradient $\nabla f$... (Thinking)
 
I like Serena said:
Hey brunette15! ;)

We can find the normal of a surface $f(x,y,z)=0$ by taking the gradient $\nabla f$... (Thinking)

Hi again I like Serena :)

I am aware that we could do that but for this particular case i am trying to prove the divergence theorem of Gauss :/
 
brunette15 said:
Hi again I like Serena :)

I am aware that we could do that but for this particular case i am trying to prove the divergence theorem of Gauss :/

Huh? :confused:

What do you want to do then?

Do you want to find the normal in polar coordinates?
If so, the method is the same - we just need the gradient in polar coordinates instead of cartesian coordinates.
 

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