Inegalitate in triunghi din gazeta matematica

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opincariumihai
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Inegalitate in triunghi din gazeta matematica

Post by opincariumihai »

Aratati ca in orice triunghi are loc inegalitatea :
\( \sum \frac{1}{a+b-c} \geq \frac{ \sqrt3}{2r}. \)

Mihai Opincariu, G.M.B. 10/2000
Marius Mainea
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Post by Marius Mainea »

Se reduce la \( \sum\tan\frac{A}{2}\ge \sqrt{3}. \)
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Cezar Lupu
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Post by Cezar Lupu »

Inegalitatea de mai sus este echivalenta dupa cateva calcule cu inegalitatea Finsler-Hadwiger, i.e.

\( a^2+b^2+c^2\geq 4S\sqrt{3}+(a-b)^2+(b-c)^2+(c-a)^2. \)
An infinite number of mathematicians walk into a bar. The first one orders a beer. The second orders half a beer. The third, a quarter of a beer. The bartender says “You’re all idiots”, and pours two beers.
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