Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple Tensor Analysis

  1. Sep 29, 2008 #1
    1. The problem statement, all variables and given/known data
    I am having trouble solving this problem. From an analysis of the behavior of a general second-rank tensor under 90 degree and 180 degree rotations about the coordinate axes, show that an isotropic second-rank tensor in 3-D space must be a multiplier of delta ij.


    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Sep 29, 2008 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Well, what does "isotropic" mean here? And how does a tensor change under rotations?
    For this problem you don't really need to look at general rotations: rotation by 90 degrees changes x to y and y to -x. Rotation by 180 degrees changes x to -x and y to -y.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook