Simile ad HM-AM ma...
Inviato: 14 ott 2011, 12:36
Dimostrate che $\forall$ $x_1,x_2,x_3\dots x_n \in [a,b]$
$$n^2 \leq \left( \sum_{j=1}^{n}x_j \right) \left( \sum_{j=1}^{n}\frac{1}{x_j}\right) \leq \frac{(a+b)^2}{4ab}n^2$$
$$n^2 \leq \left( \sum_{j=1}^{n}x_j \right) \left( \sum_{j=1}^{n}\frac{1}{x_j}\right) \leq \frac{(a+b)^2}{4ab}n^2$$