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Homework Help: Simple Vector question.

  1. Nov 27, 2011 #1
    1. The problem statement, all variables and given/known data
    This is a "exam style" question for A-Level mathematics regarding vectors. The question is as followed:

    Relative to a fixed origin O, the points A and B have position vectors 4i+3j-k and i+4j+4k respectively.

    (a) Find the vector equation of the line l1 which passes through A and B.

    The line l2 has equation r=22i+aj+4k+μ(bi-j+2k), where μ is scalar parameter and a and b are constants.
    The lines l1 and l2 are perpendicular and intersect. Find:

    (b) the values of a and b

    (c) the position vector of the point of intersection of l1 and l2

    2. Relevant equations
    Vector equation of a strait line through two points C and D:


    if there is any other ones, I am unfortunately unaware of

    3. The attempt at a solution

    Sadly I've been given no knowledge of how to do this question since vectors is not a part of my course. Therefore there are no attempts made

    This question is really getting into my head and any help would be greatly appreciated.

    Last edited: Nov 27, 2011
  2. jcsd
  3. Nov 27, 2011 #2


    Staff: Mentor

    Then why don't you wait until vectors are presented in your course, or when you take a course where vectors are presented?
  4. Nov 27, 2011 #3
    Well the reason is that I've been told by my tutor that I will not be studying vectors.
  5. Nov 27, 2011 #4


    Staff: Mentor

    Then how do you expect to be able to solve problems that involve vectors?
  6. Nov 27, 2011 #5


    User Avatar
    Science Advisor

    For this problem, all you really need to know is that a point with position vector ai+ bj+ ck has coordinates (a, b, c).
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