Eigen modes in a room

In a rectangular room 10*8*5 how can the eigen modes belonging to octave and third octave bands centered at 50Hz be found ? I have the formula to calculate the number of modes but don't have the idea how to find the modes. Do I need to use Matlab for it ?

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Have you tried an online calculator such as bobgolds.com/Mode/RoomModes.htm ? –  Alfred Centauri Sep 23 '12 at 12:46
Thanks for the link. I just have the idea but I am not able to get it completely. How is it done ? I am looking for the method and the concept behind it. –  user12448 Sep 23 '12 at 14:35