不等式1，连加号的应用

设$a_i\in R^{*}(i=1,2,...n)$,求证：$\frac{1}{a_1}+\frac{2}{a_1+a_2}+\cdots+\frac{n}{a_{1}+a_{2}+\cdots+a_{n}}\le 2\sum_{i=1}^{n}\frac{1}{a_i}$

 

转载于:https://www.cnblogs.com/zjyyhs/archive/2013/04/16/3024041.html