Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Trending News

Promoted
Pujan Gor
Pujan Gor asked in Science & MathematicsMathematics · 9 years ago

mathematical vectors?

1) reffered to a fixed point origin O, the positional vector of points P and Q are (-2i+3j) and ( ki + lj ) respectively, where k and l are constants. The point M is the midpoint of PQ. given the position vector of M relative to O is (2i+4j)

a) find the values of k and l

the point R is such that PQ : QR = 1:2

b)find, in terms of i and j, the expression for OR

1 Answer

Relevance
  • Wayne DeguMan
    Lv 7
    9 years ago
    Favorite Answer

    a) [(-2 + k)i/2, (3 + l)j/2] = (2i + 4j)

    => -2 + k = 4...i.e. k = 6

    and 3 + l = 8...i.e. l = 5

    so, OQ is 6i + 5j

    b) PQ = OQ - OP = (6i + 5j) - (-2i + 3j) = 8i + 2j

    and QR = OR - OQ = (ai + bj) - (6i + 5j)

    Now, (ai + bj) - (6i + 5j) = 2(8i + 2j)

    => (ai + bj) - (6i + 5j) = 16i + 4j

    so, (a - 6)i + (b - 5)j = 16i + 4j

    => a - 6 = 16.....i.e. a = 22

    and b - 5 = 4.....i.e. b = 9

    so, OR is (22i + 9j)

    :)>

Still have questions? Get your answers by asking now.