- #1

Shackleford

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- 2

(i) (a × b) · (c × d) = (a (i) · c)(b · d) − (a · d)(b · c).

(ii) a × (b × c) = (a · c) b − (a · b) c.

(a) Show that (i) can be derived directly from (ii). Hint: Dot (ii) with d and use the

fact that (a × b) · c = (c × a) · b, etc.

I worked on this every way I knew how last night, but I couldn't get it to work. I'm pretty sure it's something simple that I'm missing.

I've set u = (a x b), u = (c x d), etc.