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Pulling out -1 from denominator?

  1. Nov 16, 2007 #1
    I know this might seem trivial but I've never had a teacher cover this even though I've had the whole "factor out -1 from numerator " class.

    I was thinking of the cases but I haven't found a contradiction to:


    so is this always true?
  2. jcsd
  3. Nov 16, 2007 #2
    Obviously. After all (-x)/y=x/(-y)=-(x/y).
  4. Nov 16, 2007 #3


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    It's true. It's a special case of

  5. Nov 16, 2007 #4
    I've always wondered about that...
    for some reason no teacher I've had has ever done that manipulation.
  6. Nov 17, 2007 #5


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    You might try to prove the following statements:
    [tex]\frac{1}{1}=1, \frac{1}{(-1)}=(-1)*\frac{1}{1}=(-1)[/tex]
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