1. Not finding help here? Sign up for a free 30min 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!

Inerr product space question

  1. Apr 22, 2010 #1
    1. The problem statement, all variables and given/known data
    Hey, I ahve a curioisity (not homework )question.
    We learnt that there are an infinite number of inner products that can be defined ona vector space and that inner product space is what gives us the notion of distance within a given space.
    So if we defined some non standard inner product on R^n what would that mean in terms of geoemtry?
    For example, say I looked at R^2 with the standard inner product and defined a square with vectors. Then I "took a new space" in R^2 but with some other inner product and plotted the same vectors, what would they still be a square?


    Thanks
    Tal
    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 22, 2010 #2

    radou

    User Avatar
    Homework Helper

    Try to define a new norm on R^2 and see if it preserves orthogonality, for example.
     
  4. Apr 22, 2010 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Changing the inner product is essentially the same as changing your basis which, in [itex]R^n[/itex] is the same as changing your coordinate system. In particular, if you chose <(x,y),(u,v)> = xu+ 2yv as your inner product, an orthonormal basis would be [itex]\{(1, 0), (0, \sqrt{2}/2)\}[/itex] so your vertical axis would be squashed compared to your horizontal axis. No, it would not still be a square.
     
  5. Apr 22, 2010 #4
    Cool.
    Thank you.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Inerr product space question
Loading...