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Homework Help: Magnitude of perpindicular vectors

  1. May 24, 2012 #1
    1. The problem statement, all variables and given/known data

    v = (-4, -2) and need to find alll vectors of magnitude 4 that are perpindicular to v

    2. Relevant equations

    3. The attempt at a solution

    I tried
    let (x, y) be the vector of interest.

    -4x -2y = 0
    x^2 + y^2 = 16.

    Is this the right track? If so, how do i solve from here?
  2. jcsd
  3. May 24, 2012 #2


    User Avatar
    Homework Helper

    Yes, right track. Just solve the simultaneous equation pair. Substitution is the easiest way. Use the first equation to get y in terms of x, then substitute into the second.

    You should now get two values of y (remember to take both positive and negative square roots). Put that back into the first equation to get the corresponding values of x. Each solution (x,y) corresponds to a valid vector meeting the conditions.
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