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Homework Help: Calculate projections of vectors

  1. Oct 9, 2007 #1
    1. The problem statement, all variables and given/known data
    Consider the following two vectors v1= (cosx , sinx)(transpose) , v2= (-sinx , cosx)(transpose). Compute the projectors P1, P2 onto the vectors v1 and v2.

    2. Relevant equations
    (a1) (a1*,b1*) (A) <---input
    (b1) ...............(B)
    This is a matrix
    that projects on

    The snowman (one bracket over the other) is supposed to be a vector.

    3. The attempt at a solution

    I am completely lost on this situation. The textbook is extremely unclear, and there doesn't seem to be any information on line for how you go about projectors. Am I supposed to replace the input vector with v1, and then multiply it by the matrix to see what I get, or am I supposed to solve for a1 and b1, which I presume would be the projector. Any feedback would be great

    Sorry if this comes out ugly.
  2. jcsd
  3. Oct 9, 2007 #2


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    Homework Helper

    What are a1* and b1*? Is the projection you defined idempotent?
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