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Showing posts with label power mean. Show all posts
Showing posts with label power mean. Show all posts

Monday, November 23, 2009

Mean of Means

If $a_i,b_i$ are positive numbers for $i=1,\cdots,n$, and

$! M_r (a,b) = \left( \frac{a^r+b^r}{2} \right)^\frac{1}{r}$

Prove that for $0 < r < s$,

$! \displaystyle \sum M_r(a_i,b_i) \sum M_{-r}(a_i,b_i) \leq \sum M_s(a_i,b_i) \sum M_{-s}(a_i,b_i) \leq \sum a_i \sum b_i$

Thursday, November 19, 2009

3 Sequence Inequality

If $a_i, b_i, c_i$ are sequences of positive numbers for $i = 1,2,\cdots,n$, prove the following inequality:

$\sum (a_i+b_i+c_i) \sum \frac{a_ib_i + b_ic_i+ c_ia_i}{a_i+b_i+c_i} \sum \frac{a_ib_ic_i}{a_ib_i + b_ic_i+ c_ia_i} \leq \sum a_i \sum b_i \sum c_i$

where all summations are taken from $i=1$ to $i=n$. When does equality happen?