Comments by "vangrails" (@vangrails) on "Prove that the Set of 2 x 2 Diagonal Matrices with Nonzero Entries Forms a Group" video.

  1. It is more fun to proof that the set of a 2 by 2 matrices with everywhere the same value x with x not equal to 0 is a group. The determinant of such matrices is 0 but it is still a group.
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