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Math Help - help me in this prob

  1. #1
    oneplan4u
    Guest

    help me in this prob

    if
    a,b,c are R*

    and if
    a^3/bc+b^3/ac+c^3/ab > a+b+c

    prove that
    abc > 0
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  2. #2
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    Quote Originally Posted by oneplan4u
    if
    a,b,c are R*

    and if
    a^3/bc+b^3/ac+c^3/ab > a+b+c

    prove that
    abc > 0
    Is there something wrong with this problem? Because the LHS can be manipulated as,
    \frac{a^4+b^4+c^4}{abc}>a+b+c
    But if a=b=c=x then we have,
    \frac{3x^4}{x^3}>3x
    Thus,
    3x>3x
    Which is not true, perhaps you mean \geq.
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