need to explain why these are not valid, or meaningless.

1. a x (b*c)

2. (a*b) x c

3. (a*b) x (c*d)

not sure whats wrong with each of them, thankyou for any help.

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- Feb 23rd 2009, 07:19 PMrcmangowhy this doesn't work, cross product.
need to explain why these are not valid, or meaningless.

1. a x (b*c)

2. (a*b) x c

3. (a*b) x (c*d)

not sure whats wrong with each of them, thankyou for any help. - Feb 23rd 2009, 07:22 PMo_O
Recall that the dot product between two vectors gives you a

**number**.

Also recall that the cross product is defined between two vectors, not numbers.

Can you see what's wrong with your expressions? - Feb 23rd 2009, 08:24 PMrcmango
okay, so each of those have a problem because two vectors multiplied will give a number.

and then its a number x a vector, which can't happen for the cross product which looks like the case for each of them,

correct?