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Math Help - completeness axiom

  1. #1
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    completeness axiom

    if a\neq 0 and  b^2-4ac>0 then prove that the equation :

    ax^2 +bx +c =0 has a root,by using the completeness axiom in real Nos
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  2. #2
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    The solution of any of this kind of equations is:

    x_{1,2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}

    so if u have

    a\neq 0

    and

    b^2-4ac>0

    then x1 and x2 will be real numbers.

    Have a nice day,

    Hush_Hush
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  3. #3
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    I am sorry, you have misread my post, i said prove the existence by using the completeness axiom.

    To use the square root you must prove 1st that it exists.

    How do you know that for all a, b, c and such that a\neq 0

    and b^2-4ac>0 :

    \frac{- b\pm\sqrt{b^2-4ac}}{2a} exists??
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