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Homework Help: I'm stuck to prove Nilpotent Matrix

  1. Oct 17, 2006 #1
    Hi all,
    If a square matrix A of dimension n*n is a nilpotent matrix,i.e, A^k=0 for k>=m iff A has eigenvalues 0 with multiplicity n and index m or less. I did prove by induction if A^k=0 then all the eigenvalues are zero. I'm lost when I want to prove the oppesite, i.e, if all eigenvalues are zero then A^k=0? Please help
  2. jcsd
  3. Oct 17, 2006 #2

    matt grime

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    Science Advisor
    Homework Helper

    Put it in jordan normal form and it all drops out. Alternatively just think about the characteristic poly.
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