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Inegalitate "nice"
Posted: Wed Aug 06, 2008 8:41 pm
by Claudiu Mindrila
Fie \( a,b,c \in \mathbb{R}^*_+ \). Demonstrati inegalitatea:
\( \frac{\sqrt{a}}{(a+b)(a+c)}+\frac{\sqrt{b}}{(b+a)(b+c)}+\frac{\sqrt{c}}{(c+a)(c+b} \leq \frac{3}{4\sqrt{abc}} \).
Re: Inegalitate "nice"
Posted: Wed Aug 06, 2008 9:18 pm
by Marius Mainea
Claudiu Mindrila wrote:Fie \( a,b,c \in \mathbb{R}^*_+ \). Demonstrati inegalitatea:
\( \frac{\sqrt{a}}{(a+b)(a+c)}+\frac{\sqrt{b}}{(b+a)(b+c)}+\frac{\sqrt{c}}{(c+a)(c+b} \geq \frac{3}{4\sqrt{abc}} \).
Poate
\( \frac{\sqrt{a}}{(a+b)(a+c)}+\frac{\sqrt{b}}{(b+a)(b+c)}+\frac{\sqrt{c}}{(c+a)(c+b} \leq \frac{3}{4\sqrt{abc}} \) 
Posted: Wed Aug 06, 2008 9:22 pm
by Claudiu Mindrila
Aveti dreptate. Am modificat.
Posted: Wed Aug 06, 2008 10:29 pm
by Marius Dragoi
\( \sum_{} {\frac {\sqrt {a}}{(a+b)(a+c)} \) \( \leq \) \( \sum_{} {\frac {\sqrt {a}}{4 \sqrt {a^2bc}} \) \( = \) \( \frac {3}{4 \sqrt {abc}} \)
Posted: Thu Aug 07, 2008 10:56 pm
by Claudiu Mindrila
Asta a fost si solutia mea Marius. Insa daca vrei o inegalitate draguta, incearca
aici .