Calculating Surface Integrals Using the Divergence Theorem

liishii
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Homework Statement


Evaluate the double integral over M (F \circ dS) where M is the surface of the sphere of radius 3 centered around the origin. (Sorry! I couldn't figure out how to use math symbols!)


Homework Equations


double integral(F\bulletdS)=triple integral (\nabla\bullet F)dV due to the divergence thm.


The Attempt at a Solution


I used the divergence theorem and got triple int(3y^2+3x^2+3z^2) dx dy dz with the limits z=-3 to 3, y=-\sqrt{}3-z^2 to \sqrt{}3-z^2 , x=-\sqrt{}3-y^2-z^2 to \sqrt{}3-y^2-z^2 . I plugged this into wolfram alpha but the answer i get isn't the right answer...

THanks in advance for the help!
 
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Greetings! Did you try using spherical coordinates? This will make the computation much easier, as well as make any mistakes easy to identify.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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