How to calculate a integral on boundary

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SUMMARY

The integral calculation discussed involves the expression \(\oint_{\Sigma}f(x,y)g(x,y)\mathbf{n}\cdot d\mathbf{s}\) where \(g(x,y)=0\) on the boundary \(\Sigma\). It is established that if the integrand \(g(x,y)\) is zero on the boundary, the integral evaluates to zero. This conclusion is supported by the fundamental properties of integrals in vector calculus, specifically when the integrand is identically zero.

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Stole
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Hi,
I would like to calculate the following integration:

\oint_{\Sigma}f(x,y)g(x,y)\mathbf{n}\cdot d\mathbf{s}

where g(x,y)=0 on \Sigma, and \mathbf{n} is the outward pointing unit normal field of the boundary \Sigma.

In this case does the integral equals to 0?

Thanks!
 
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Stole said:
Hi,
I would like to calculate the following integration:

[tex]\oint_{\Sigma}f(x,y)g(x,y)\mathbf{n}\cdot d\mathbf{s}[/tex]

where g(x,y)=0 on[itex]\Sigma[/itex], and [/itex]\mathbf{n}[/itex] is the outward pointing unit normal field of the boundary \Sigma.

In this case does the integral equals to 0?

Thanks!
You forgot the [ tex ] and [ /tex ] tags!
Yes, if your integrand is always 0, the integral is 0. Isn't that obvious?
 

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