Can you apply Stoke's theorem to this?

In summary, the conversation discusses the surface area of a hemi-sphere of radius 6 centered at the origin above the xy-plane lying outside the cylinder r2 = 9. The attempted solution involved using algebra and a formula, resulting in a surface area of 324π. The question of whether there is an easier way to find the surface area is raised, with the relationship to the curl of a vector field also being mentioned. Stoke's theorem and its application to surface area is briefly discussed.
  • #1
flyingpig
2,579
1

Homework Statement



What is the surface area of a hemi-sphere of radius 6 centered at the origin above the xy-plane lying outside the cylinder r2 = 9


The Attempt at a Solution



I did a lot of algebra using the hard way by setting [tex]z = \sqrt{6^2 - x^2 - y^2}[/tex] and use the formula

[tex]A(S) = \iint \sqrt{1 + \left(\frac{\partial z}{\partial x}\right)^2 + \left(\frac{\partial z}{\partial y}\right)^2} dA[/tex]

Did a lot of messy algebra and got 324π

Is there an easier way to do this?
 
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  • #2
If you could, wouldn't that imply that the surface area of any figure with the same bounding curve be 324π? Also I don't see how you would get the surface area in terms of curl of a vector field.
 
  • #3
Surface area somehow relates to surface integral...

Never mind, I will trsut in my own answer.
 
  • #4
Yes, but not necessarily to the curl of a vector field.
 
  • #5
Hurkyl said:
:confused:

Stoke's theorem says that the surface integral of the curl of a vector field is equal to the loop integral of the vector field over the bounding curve, right?
 
  • #6
Yeah...?
 
  • #7
Never mind, it seems Hurkyl deleted that post.
 

1. Can you explain what Stoke's theorem is?

Stoke's theorem is a mathematical principle that relates the surface integral of a vector field over a surface to the line integral of the same vector field along the boundary of that surface.

2. How is Stoke's theorem used in science?

Stoke's theorem is frequently used in physics and engineering to calculate the flow of a vector field through a given surface. It allows scientists to relate a complex 3-dimensional problem to a simpler 2-dimensional problem.

3. Can you provide an example of applying Stoke's theorem?

One example of applying Stoke's theorem is in electromagnetics, where it is used to calculate the circulation of an electric or magnetic field around a closed path.

4. Is Stoke's theorem applicable in all situations?

No, Stoke's theorem is only applicable in certain situations where the vector field and the surface satisfy certain conditions. For example, the surface must be smooth and the vector field must be differentiable.

5. Can Stoke's theorem be extended to higher dimensions?

Yes, Stoke's theorem can be extended to higher dimensions through the use of differential forms and the generalized Stokes' theorem.

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