prove that

Δ.(ΨΔφ x φΔΨ)=0

where Δ is delta.

anybody help plz

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- Nov 16th 2013, 06:32 AMMathGeni04Vector identites question
prove that

Δ.(ΨΔφ x φΔΨ)=0

where Δ is delta.

anybody help plz - Nov 16th 2013, 02:41 PMchiroRe: Vector identites question
Hey mathgeni04.

Hint: Expand all the vectors out in terms of <x,y,z> terms and use the definition of the dot and cross products. - Nov 16th 2013, 03:11 PMPlatoRe: Vector identites question
I do not disagree with reply #2 but I do wonder if by $\displaystyle \Delta$ you really mean $\displaystyle \nabla =i \frac{\partial }{{\partial x}} +j \frac{\partial }{{\partial y}} + k\frac{\partial }{{\partial z}}~?$

That is 'nabla' or the del operator. If not what does $\displaystyle \Delta$ mean? - Nov 18th 2013, 07:18 PMMathGeni04Re: Vector identites question
\Delta is del operator.

- Jan 5th 2014, 05:58 AMPeteRe: Vector identites question
- Jan 6th 2014, 06:22 AMHallsofIvyRe: Vector identites question
So you

**really**mean "$\displaystyle \nabla \cdot ((\nabla \psi)\phi \times \psi(\nabla\phi))= 0$"? - Jan 8th 2014, 08:45 AMPeteRe: Vector identites question
Thanks HallsofIvy. If that were the case then the whole thing makes sense, if it's an actual identity that is.