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Math Help - Unit Vector Question

  1. #1
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    Unit Vector Question

    The question I am having problems with is:

    Find a unit vector perpendicular to u = i+3k

    and v = 2j-k.

    Can anyone help me solve this?

    I know that u.v = 0 if they are perpendicular, thanks.
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  2. #2
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    are you familiar with cross products ? if so your answer is given by \frac{u \times v}{|u \times v|}
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  3. #3
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    Yeh I can do cross products, thanks for the very quick responce and help!
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  4. #4
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    I also have a problem solving this question:

    Find the values of a and b such that u = (1,a,2b) and v = (-3,1,4) are parallel. I tried equating the terms but I'm not getting anywhere. a+8b-3=0. Can you help?
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  5. #5
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    Quote Originally Posted by haku View Post
    I also have a problem solving this question:
    Find the values of a and b such that u = (1,a,2b) and v = (-3,1,4) are parallel. I tried equating the terms but I'm not getting anywhere. a+8b-3=0.
    Please always start a new thread, do not add to an existing one.
    You want to find values such that \frac {1}{-3} = \frac {a}{1} = \frac {2b}{4}.
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