1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Linear Algebra: Dot Product and Orthogonality

  1. Sep 27, 2011 #1
    This is from my homework, I was moving along nicely until I hit this problem, (there's another just like it right after this). I can't find reference for solving this in the chapter Im looking at. The answer is in the back of the book….-2911. Can someone explain this to me?


    [tex]
    ||\mathbf{u}|| = 5\, and\: ||\mathbf{v}|| = 7; \,find\: (3\mathbf{u} - 8\mathbf{v}) \circ (3\mathbf{u} + 8\mathbf{v}).
    [/tex]


    I know that [itex]||\mathbf{u}||[/itex] is just the length of the vector, etc. I just don't know where to go from there.
     
  2. jcsd
  3. Sep 27, 2011 #2

    lanedance

    User Avatar
    Homework Helper

    try expanding the dot product using its linear properties, should simplify a heap
     
  4. Sep 27, 2011 #3
    You were right. Solved it first go after that. Thank you.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Linear Algebra: Dot Product and Orthogonality
Loading...