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Math Help - Cross product - associativity

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    Cross product - associativity

    To prove that cross product is not associative, check that (j*k)*k doesn't equal j*(k*k)

    How would I go about doing this?
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    Quote Originally Posted by brumby_3 View Post
    To prove that cross product is not associative, check that (j*k)*k doesn't equal j*(k*k)

    How would I go about doing this?
    I assume that i, j and k are unit vectors in the directions of the three coordinate axes. You ought to know that, for example, i*j = k, and i*i = 0.

    So, how would you go about doing this? All I can suggest is that you should just ... do it.
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