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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- Apr 22nd 2006, 09:04 AMoneplan4uhelp 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 - Apr 22nd 2006, 07:04 PMThePerfectHackerQuote:

Originally Posted by**oneplan4u**

$\displaystyle \frac{a^4+b^4+c^4}{abc}>a+b+c$

But if $\displaystyle a=b=c=x$ then we have,

$\displaystyle \frac{3x^4}{x^3}>3x$

Thus,

$\displaystyle 3x>3x$

Which is not true, perhaps you mean $\displaystyle \geq$.