Page 1 of 1

ineg

Posted: Sun Oct 26, 2008 5:47 pm
by BogdanCNFB
Fie \( n\ge 3 \) si \( a_1,a_2,...,a_n\in(0,\propto) \) cu \( s=a_1+a_2+...+a_n \).
Sa se arate ca \( \prod_{k=1}^n(s-(n-1)a_k)\leq a_1a_2\cdot...\cdot a_n \).

Posted: Sun Oct 26, 2008 10:19 pm
by Marius Mainea
Notand \( x_k=S-(n-1)a_k \) , \( k=\overline{1,n} \) , inegalitatea devine \( \prod_{k=1}^nx_k\le \frac{(x_1+x_2...+x_{n-1})....(x_2+x_3+...+x_n)}{(n-1)^n} \) ceea ce se demonstreaza usor folosind inegalitatea mediilor.