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Homework Help: Two-thirds between vectors

  1. Sep 20, 2010 #1
    The question is: Use vectors to find the point that lies two-thirds of the way from P to Q.

    P: (1,2,5)
    Q:(6,9,5)

    I tried finding the distance, then multiplying by 2/3 but obviously that will yield a scaler. Tried multiplying 2/3 by every coordinate then add them? That didn't work. I am sort of lost on such a simple problem :uhh:

    Thank you in advance for any attempt made :)
     
  2. jcsd
  3. Sep 20, 2010 #2
    Think about a vector that would join the tip of P to the tip of Q.
     
  4. Sep 20, 2010 #3
    a little more push? lol We learned about tip-to-tail method. no tip-to-tip that i know of
     
  5. Sep 20, 2010 #4
    Well if you can find the vector that joins the tip of P to the tip of Q, then you take two-thirds of that vector, add it to P, and you are two-thirds of the way to the tip of Q.

    Tto go from the tip of A to the tip of B, you need the vector B-A. Make sense yet?
     
    Last edited: Sep 20, 2010
  6. Sep 20, 2010 #5
    Yeah, I got it after that last post of mine >_<. Sometimes I'm used to thinking so complex that I forget about just visualizing the concept first lol. Thanks a whole bunch :D
     
  7. Sep 20, 2010 #6

    Mark44

    Staff: Mentor

    "visualizing the concept" - whenever possible, visualize the concept by drawing a picture. You're using another half of your brain when you have an image to work with, instead of just the half that deals with logic and equations and such.
     
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