Can you apply Stoke's theorem to this?

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Homework Help Overview

The problem involves calculating the surface area of a hemisphere of radius 6 centered at the origin, specifically the portion above the xy-plane and outside the cylinder defined by r² = 9. The original poster attempts to use a surface integral approach to find this area.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the original poster's algebraic approach and question whether there is a simpler method. There is also a consideration of the implications of using Stoke's theorem in this context, particularly regarding the relationship between surface area and the curl of a vector field.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and questioning the applicability of Stoke's theorem. Some participants express uncertainty about the relationship between surface area calculations and vector fields.

Contextual Notes

There is a mention of the original poster's concern about the complexity of their algebraic solution and the implications of applying Stoke's theorem to this specific problem. The discussion reflects a lack of consensus on the best approach to take.

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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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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.
 
Surface area somehow relates to surface integral...

Never mind, I will trsut in my own answer.
 
Yes, but not necessarily to the curl of a vector field.
 
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?
 
Yeah...?
 
Never mind, it seems Hurkyl deleted that post.
 

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