摘要：Problem 12067 - 08 - P. Bracken (USA). 对于正整数$n$.令$$\beta_n=6n+12n^2(\gamma-\gamma_n),$$其中$\gamma_n=H_n-\ln n$, $\displaystyle H_n=\sum_{j=1}^n\frac{1} 阅读全文

摘要：(Fejer-Jackson-Growall不等式) 1910年Fejer猜想,三角函数级数\[\frac{\pi-x}{2}=\sum_{k=1}^{\infty}\frac{\sin kx}{k},\quad 0<x\leq\pi\]的所有部分和\[S_n(x)=\sum_{k=1}^{n}\f 阅读全文

摘要：For the elliptic integral of first kind, $K(m)=\int_0^{\pi/2}\frac{d\theta}{\sqrt{1-m^2sin^2\theta}} $, it is well-known that $K(m)$ can be expressed 阅读全文

摘要：The following is probably a math contest problem. I have been unable to locate the original source. Suppose that $\{a_i\}$ is a set of positive real n 阅读全文

摘要：壁纸：C:\Users\Administrator\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\LocalState\Assets C:\Users\%username%\AppData\ 阅读全文

摘要：IBM平面几何难题：https://www.research.ibm.com/haifa/ponderthis/challenges/August1998.html We have a triangle ABC, with a point D on side AB, E, on side BC, a 阅读全文