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Homework Help: Infimum proof

  1. Oct 30, 2012 #1
    1. The problem statement, all variables and given/known data

    Giva a formal proof that 3/4 is the infimum of the set : A = { x^2 +x + 1 }

    2. Relevant equations
    I need a clear way to prove it - to understand the contradiction.


    3. The attempt at a solution
    I've assumed there is a M<3/4 that x^2 +x + 1>M. where is the contradiction?
     
  2. jcsd
  3. Oct 30, 2012 #2

    mfb

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    2017 Award

    Staff: Mentor

    I think you mean ##x^2 +x + 1\leq M##? Otherwise it would be a bit pointless.

    You should have given ##x \in R## somewhere.
     
  4. Oct 30, 2012 #3

    HallsofIvy

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    Science Advisor

    Why is this posted under "physics"? It is clearly a math problem- complete the square.
     
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