# Quod Erat Demonstrandum

## 2013/04/28

### 摺紙條

Filed under: Fun — johnmayhk @ 6:56 下午

### [Trailer] Crimes A Oxford

Filed under: Fun — johnmayhk @ 5:37 下午

Just found a trailer of an old film in 2008…

(more…)

## 2013/04/24

### 某校內講座

Filed under: School Activities — johnmayhk @ 4:23 下午

### To f.4 M2 of my group

Filed under: NSS — johnmayhk @ 3:05 下午

In the recent sudden quiz, there is a so-called bonus question (actually it is a boring 1-mark question): evaluate

$\displaystyle \lim_{n\rightarrow \infty}(\sqrt[8]{n^2+1}-\sqrt[4]{n+1})$.

Here is a suggested (more…)

## 2013/04/15

### Cosine law

Filed under: mathematics,NSS — johnmayhk @ 11:52 上午

https://johnmayhk.wordpress.com/2010/10/24/a-short-m2-question/

（即紅線都是大圓弧。）

$\angle AOB=c'$
$\angle BOC=a'$
$\angle COA=b'$

$a=Ra'$
$b=Rb'$
$c=Rc'$

$R=1$，則所謂球面上的 cosine law 者：

$\cos a=\cos b\cos c+\sin b\sin c\cos A$
$\cos b=\cos c\cos a+\sin c\sin a\cos B$
$\cos c=\cos a\cos b+\sin a\sin b\cos C$

### 你今日 google O左未？

Filed under: Fun — johnmayhk @ 8:31 上午

## 2013/04/13

### 小定理

Filed under: Fun — johnmayhk @ 2:21 下午

## 2013/04/12

### …

Filed under: Fun — johnmayhk @ 1:50 下午

Intellectuals solve problems, geniuses prevent them. (Albert Einstein)

### partial fractions

Filed under: Junior Form Mathematics,NSS — johnmayhk @ 1:46 下午

http://www.wolframalpha.com

## 2013/04/06

### [FW] Story of Maths – BBC

Filed under: Fun — johnmayhk @ 1:23 下午

（共四集：The Language of the Universe; The Genius of the East; The Frontiers of Space; To Infinity and Beyond）

http://en.wikipedia.org/wiki/The_Story_of_Maths

## 2013/04/03

### 某些題

Filed under: Fun — johnmayhk @ 12:29 下午

## 2013/04/02

### 無限朱古力

Filed under: Fun — johnmayhk @ 7:13 下午