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Homework Help: Computing inner products in C

  1. May 25, 2009 #1
    1. The problem statement, all variables and given/known data x=(2,1+i,i) and y=(2-i,2,1+2i)

    2. Relevant equations

    3. The attempt at a solution um ok normally i would use <a,b>=|a||b|cos(theta). But these are complex numbers. I have no clue how to do this.
  2. jcsd
  3. May 25, 2009 #2


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    Surely you have a definition to appeal to?

    (and I'm pretty sure that <a,b>=|a||b|cos(theta) isn't it -- and even if that equation were correct, it is rare that you'd actually want to use it to compute an inner product)
  4. May 25, 2009 #3

    D H

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    Suppose instead you were just working with real vectors -- say (2,20,2) and (10,1,1). There is no need to compute the angle between these vectors. There is a much easier way to do this. What is another way to compute the inner product that |a||b|cos(theta)? How would you generalize this to complex numbers?

    And finally, what is in your class notes and text? I am quite certain your instructor does not expect you to derive the formula for computing the inner product in C3. He or she expects you to use something you have already been taught.
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