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A Little Help Vector Calculus Problem

  1. Sep 18, 2005 #1
    the problem goes:

    ABCD is a parallelogram in which points P and Q are the midpoints of sides BC and CD, respectively. Use vector calculus to prove that AP and AQ trisect the diagonal BD at the points E and F.

    .....A _________B
    (Imagine lines from D->B, A->Q and A->P, where AQ passes through E and AP passes through F)

    I set the Problem Up like this:
    DE = x(DA + AB)
    EF = y(DA + AB)
    FB = z(DA + AB)

    After this I get stuck running around in circles trying to make subsitutions to show that x, y & z = 1/3.

    Ideas anyone?
  2. jcsd
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