- #1
Archduke
- 59
- 1
Homework Statement
Prove:
[tex]\int\left(\nabla \times \vec{F}\right)\cdot d\vec{V} = \oint \left(\vec{\hat{n}} \times \vec{F} \right) dS [/tex]
Homework Equations
In the previous part of the question, we proved that:
[tex]\nabla \cdot \left( \vec{F} \times \vec{d} \right) = \vec{d} \cdot \nabla \times \vec {F} [/tex]
(where d is a constant vector)
And also, it looks like we'll need to use the Divergence theorem.
The Attempt at a Solution
OK, so, here I go!
[tex] \int\left(\nabla \times \vec{F} \right)\cdot \vec{\hat{n}}dV \\
= \int \nabla \cdot \left( \vec{F} \times \vec{\hat{n}} \right) dV [/tex]
By the relation above proved from the previous part of the question. Next, I used the divergence theorem:
[tex]
\int \nabla \cdot \left( \vec{F} \times \vec{\hat{n}} \right) dV = \oint \left( \vec{F} \times \vec{\hat{n}} \right) \cdot d\vec{S} [/tex]
My question is...Is [tex] \oint \left( \vec{F} \times \vec{\hat{n}} \right) \cdot d\vec{S} = \oint \left(\vec{\hat{n}} \times \vec{F} \right) \cdot d \vec{S} [/tex]?
My initial thought is that it isn't, as the cross product isn't commutative. If that is thecase, where else have I gone wrong?
Cheers!