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How can we prove that the inverse of an upper (lower) triangular matrix is upper (lower) triangular?

  • 2
    Why not try a constructive proof? Better yet, look at the 2-by-2 case first, and figure out how you can generalize your observations from it.2010-09-17
  • 3
    A further hint: look up "forward elimination" and "backsubstitution", and figure out how to use these to find the inverse of a triangular matrix.2010-09-17
  • 0
    Try http://www.math.lsa.umich.edu/~tfylam/Math217/proofs05-sol.pdf2013-12-10

6 Answers 6