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Math Help - Supremum

  1. #1
    Super Member Showcase_22's Avatar
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    Supremum

    Sup {x \in \Re: x^2+4x+1<0}

    I'm not sure how to get the set brackets up so here it is without the math bits next to it:

    Sup {x \in \Re: x^2+4x+1<0}

    What's the answer?
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  2. #2
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    Did you graph x^2 +4x +1?
    What is the larger of the two roots?
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  3. #3
    Super Member Showcase_22's Avatar
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    Well I can use the quadratic formula to get \frac{-4 + \sqrt {4^2-4}}{{2}}=\frac{-4 + \sqrt{12}}{2}=\frac{-4 + 2 \sqrt 2}{2}=-2+\sqrt 2.

    I was just thinking that the answer would be zero since the greatest value of x^2+4x+1 is 0. I can see what I was doing wrong now.

    cheers!
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