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Math Help - why this doesn't work, cross product.

  1. #1
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    why 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.
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  2. #2
    o_O
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    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?
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  3. #3
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    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?
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