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Homework Help: Prime Division HELP

  1. Nov 2, 2011 #1
    Prime Division HELP!!!

    1. The problem statement, all variables and given/known data

    I need to be able to understand and likely prove that for any positive odd integer n,
    8 | (n^2 -1 )

    2. Relevant equations

    3. The attempt at a solution
    odd can be said to be n = 2k +1
    so 8 | (2k + 1)^2 -1
  2. jcsd
  3. Nov 2, 2011 #2


    User Avatar
    Science Advisor

    Re: Prime Division HELP!!!

    Keep going. Now expand out (2k+1)^2 - 1 and collect terms. Then think about the terms in k and k+1.
  4. Nov 2, 2011 #3
    Re: Prime Division HELP!!!

    I got stumped trying mathematical induction i was hoping for a new approach
  5. Nov 2, 2011 #4


    Staff: Mentor

    Re: Prime Division HELP!!!

    Try the approach that phyzguy is suggesting.
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