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Contrapositives are confusing

  1. Apr 16, 2015 #1
    I'm a bit confused on how to apply contrapositives... This isn't for homework but I'm attempting to show that if n^2 + 2 is prime that 3|n.

    I'm wondering if this is an appropriate time for me to show the contrapositive of the statement to be true, therefore the original statement to be true.

    Contrapostive: if 3 does not divide n, then n^2+2 is not prime.

    I know how to show this contrapositive to be true...

    Am I doing this right?
  2. jcsd
  3. Apr 16, 2015 #2


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