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I Prove that A:B is greater than C:D?

  1. Mar 26, 2016 #1
    From "Road to Reality" chapter 3 part two. If three ratios are known: M:N, A:B, C:D. A:B is greater than C:D if: A added to itself M times exceeds B added to itself N times and D added to itself N times exceeds C added to itself M times. Show that the ratio A:B is greater than C:D.
     
  2. jcsd
  3. Mar 26, 2016 #2

    cnh1995

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    I believe this should be posted in maths forum.
    Based on the data,
    A(M+1)>B(N+1) and D(N+1)>C(M+1)
    So,
    A/B>(N+1)/(M+1).......(1)
    and
    C/D<(N+1)/(M+1).......(2)
    1 and 2 clearly prove A:B>C:D.
     
  4. Mar 26, 2016 #3
    Thank you, it does belong to the mathematics category, but I'm unsure how to change it
     
  5. Mar 26, 2016 #4

    cnh1995

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    You can't change it once you've posted it. A mentor will fix it.
     
  6. Mar 26, 2016 #5
    Ah I see. Once again, thank you, I suppose for some reason I struggled with an otherwise simple question.
     
  7. Mar 26, 2016 #6

    HallsofIvy

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    This is assuming all the numbers involved are positive.
     
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