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P6 vector qustion.. 'Hence' calculate volume ? watch

    • Thread Starter

    hiya, it's vector again giving me trouble.

    this question is from Heinemann P6 textbook Ex4B Q10.

    ---------------->question begins!!

    The points A, B, C, D have position vectors

    a = (2i + j)
    b = (3i - j + k)
    c = (-2i - k)
    d = (2i - j +3k) respectively.

    (a) Find AB X BC and BD X DC.
    (b) Hence find
    (i) the area of ABC
    (ii) the volume of the tetrahedron ABCD.

    yeah.. didn't have a clue for (b)(ii).
    i mean, i can do it by usual formula, but the question specifically asked for 'hence'. Is there a way to do it using AB X BC and BD X DC?

    Any suggestion would be grateful

    It's still an application of the formula. The "hence" part is there because you already have the bxc part, I believe.
    • Thread Starter

    so i see..

    haha.. the question scared me! thanks anyway
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Updated: June 25, 2005
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