Page 1 of 1

Shortlist 11

Posted: Sun Mar 28, 2010 8:22 pm
by Antonache Emanuel
Fie a,b,c numere strict pozitive satisfacand \( a^3+b^3+c^3=1 \). Aratati ca:
\( \sum log_a (\sqrt[3]3bc)>0 \).
I. V. Maftei, Bucuresti

Posted: Sun Mar 28, 2010 11:35 pm
by Marius Mainea
Notam \( x=a^3 \) si analoagele si inegalitatea se reduce la

\( \sum \log_x3yz>0 \) cu x,y,z pozitive cu \( x+y+z=1 \)