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Math Help - || u + v || = ?

  1. #1
    s3a
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    || u + v || = ?

    Can someone please explain this question to me?

    Thanks!
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  2. #2
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    Quote Originally Posted by s3a View Post
    Can someone please explain this question to me?

    Thanks!

    u = AB = A(-5,7) to B(3,-5) indicates that vector u = (8,-12)


    where u = (8,-12) 8 are horizontal units from A to B
    AND -12 are vertical units from A to B

    now ||u+v||= \sqrt{(6+8)^2+ (3-12)^2}

    = \sqrt{(14)^2+ (-9)^2}

    = \sqrt{196+ 81}

    = \sqrt{277}
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  3. #3
    s3a
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    I'm assuming the AB thing has to with Head - Tail stuff but why is it B - A and not A - B for example?
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    Quote Originally Posted by s3a View Post
    I'm assuming the AB thing has to with Head - Tail stuff but why is it B - A and not A - B for example?
    The order of these letters matter as they describe dierection.

    AB (with the little arrow on top) means from A to B. Where BA means from B to A.

    Consider AB = (8,-12) ans BA = -AB

    so BA = -(8,-12) =(-8,12)
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  5. #5
    s3a
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    Ok so AB means A is the tail and B is the head and since it's Head - Tail, it's B - A? (just saying it in my own words to see if I understand)
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