$\sum_{i=1}^{n}x_{i}\geq C(n)\sum_{1\leq j<i\leq n}(2x_{i}x_{j}+\sqrt{x_{i}x_{j}})$
đúng với mọi $x_i \in (0,1),i=1,..,n$ và $(1-x_{i})(1-x_{j})\geq\dfrac{1}{4},1\leq j<i \leq n$.
$\sum_{i=1}^{n}x_{i}\geq C(n)\sum_{1\leq j<i\leq n}(2x_{i}x_{j}+\sqrt{x_{i}x_{j}})$
Learn from yesterday,live for today,hope for tomorrow
The important thing is to not stop questioning
0 thành viên, 1 khách, 0 thành viên ẩn danh