$\vec{u},\vec{w},\vec{v}\in\mathbb{R^3}$ $(\vec{u}\times\vec{w})\times \vec{v}=0$ if an only if $(\vec{u}\times\vec{v})\times \vec{w}= \vec{u}\times(\vec{v}\times \vec{w})$ is it always true and how to prove it?
Question about a prove in cross product
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calculus
1 Answers
3
$\newcommand{\t}{\times}$ Note that the expression
$(u\t w)\t v + (w\t v)\t u + (v\t u)\t w$
can be expanded using the vector triple product and shown to be equal to zero.
The result you are asked to prove follows easily.