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Homework Help: Simple vectors question

  1. May 14, 2008 #1
    1. The problem statement, all variables and given/known data

    Check the picture.

    2. Relevant equations

    3. The attempt at a solution

    I'm sure it's very simple but I just can't seem to get it. I've been sitting here staring at the page for a while now with no joy. Check the picture for my attempt.
    Thanks very much for any help, greatly appreciated.

    Attached Files:

  2. jcsd
  3. May 14, 2008 #2
    Can anyone help with this?
  4. May 14, 2008 #3


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    Homework Helper

    well you are correct in saying that [itex]\hat{b}=\frac{\vec{ab}}{|ab|}[/itex] and that [itex]\hat{c}=\frac{\vec{ac}}{|ac|}[/itex].

    and if [itex]\vec{ad} = t( \hat{b} - \hat{c})[/itex] what does that tell you about the direction of that vector?

    How would you find the vector bc?

    then how do you get the angle between two vector lines?
  5. May 14, 2008 #4
    Ah I see it now so [itex] \vec{ad} = t ( \hat{cb} ) [/itex]
    Therefore [itex] \vec{ad} [/itex] is perpendicular to [itex] \hat{cb} [/itex]
    Therefore [itex] \vec{ad} [/itex] is the perpendicular bisector of the the line bc.
    Thank you very much for your help!
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