Is there a vector proof for (u x (v+w)) . r = (u . w)(v . r) - (u . v)(w . r)?

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The discussion revolves around proving the vector identity (u x (v+w)) . r = (u . w)(v . r) - (u . v)(w . r). A participant has simplified the left-hand side to (r x u) . v + (r x u) . w but is unsure how to proceed. There is uncertainty about whether the proof can be completed using only vector identities without resorting to components. Another participant suggests that the original equation may contain a misprint and proposes an alternative identity to prove instead. The conversation highlights the challenges in vector proofs and the importance of clarity in mathematical statements.
Bipolarity
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Homework Statement


Show that (u \times (v+w))\cdot r = (u \cdot w)(v \cdot r) - (u \cdot v)(w \cdot r)

Homework Equations





The Attempt at a Solution


So far I have been able to simplify the LHS to:
(r \times u)\cdot v + (r \times u) \cdot w but don't know how to proceed from there.

In fact, I don't know if this problem is even solvable using only vector identities, i.e. without having to prove using components.

All help is appreciated!

BiP
 
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Hi Bipolarity! :smile:

It's a misprint :rolleyes:

try (u \times (v \times w))\cdot r = (u \cdot w)(v \cdot r) - (u \cdot v)(w \cdot r) :wink:
 
Thanks tiny-tim!

BiP
 
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