(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Prove that [tex]2A=\oint \vec{r}\times d\vec{r}[/tex]

2. Relevant equations

3. The attempt at a solution

From stokes theorem we have [tex]\oint d\vec{r}\times \vec{r}=\int _{s}(d\vec{s}\times \nabla)\times \vec{r}= \int _{s}(2ds\frac{\partial f}{\partial x},-ds+ds\frac{\partial f}{\partial y},-2ds)[/tex]. I'm stuck here and I don't know how to continue. Please help me.

Another method is [tex]\oint \vec{r}\times d\vec{r}=\oint (ydz-zdy,zdx-xdz,xdy-ydx)[/tex]. Please help me solve it.

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# Homework Help: Stokes theorem and line integral

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