i) Show that: a x ( b x c) + b x ( c x a) + c x (a x b ) =0(adsbygoogle = window.adsbygoogle || []).push({});

I managed to this, by expanding each term using the definition of the triple vector product i.e. a x ( b x c) = (a.c)b-(a.b)c and adding the results.

ii) and deduce that

a x { b x ( c x d ) } + b x { c x ( d x a ) } + c x { d x ( a x b) } + d x { a x ( b x c ) } =

( a x c ) x ( b x d)

I expanded each term like i did in the first an added the results an obtained:

-(d x b)(b.a) - (d.a)(c x b) - (b x a)(c.d) - (b.c)(a x d )

Clearly the result does not agree, and I can't find any means how to simplify it. Some help anyone? Thanks

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# Homework Help: Vector proof

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