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Discrete math proofs help.

  1. Mar 24, 2009 #1
    If m and n are positive integers, (mn)!=m!n! Prove or disprove.

    its so obviously true i can't prove it. anyone help?

    -also-

    Prove: The square root of a prime integer is an irrational number.

    any help?
     
  2. jcsd
  3. Mar 24, 2009 #2
    (3*2)! = 720 =/= 3!2! = 12

    So it's actually FALSE.
     
  4. Mar 24, 2009 #3
    hah wow, that shows how long i haven't slept.

    any idea on the 2nd question?
     
  5. Mar 24, 2009 #4
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