# Quod Erat Demonstrandum

## 2010/02/28

### 有關高耀潔醫生

Filed under: Life,Report — johnmayhk @ 6:57 下午
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(明報)2009年12月2日 星期三 05:25

【明報專訊】中國民間防愛滋第一人、日前低調抵達美國的82歲河南醫生高耀潔昨日藉「世界愛滋病日」在華盛頓召開記者會，講述中國愛滋病疫情現?及介紹其新書《血災：10000封信》。高耀潔撰寫的發言稿中表示，自己年事已高，「此行（美國）明知是埋骨異地」，暗示自己將不會返國。而有生之年要把中國愛滋受害者的真實情?整理成書出版，否則「死不瞑目」。她在接受BBC訪問時也透露，中國愛滋病患者2006年已有84萬，衛生部現時公布的74萬人並不正確。 (more…)

### 最大可能和期望值

Filed under: Additional / Applied Mathematics,HKALE — johnmayhk @ 12:04 上午

$X$ ~ $B(n , p)$
$P_k = P(X = k)$ （其中 $k = 0, 1, \dots n$

## 2010/02/27

### 有關 sin(x)/x 接近 1 的循環論證

Filed under: HKALE,Pure Mathematics — johnmayhk @ 12:19 上午
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$\displaystyle \lim_{x \rightarrow 0+}\frac{\sin x}{x}$

## 2010/02/26

### 獨立隨機變量

Filed under: Additional / Applied Mathematics,HKALE — johnmayhk @ 7:47 上午

$X, Y, Z$ 是互相獨立（mutually independent）的隨機變數，其平均數及方差分別是 $\mu_1, \mu_2, \mu_3$$\sigma^2_1, \sigma^2_2, \sigma^2_3$，可否尋求 $Var(XY + YZ + ZX)$

$Var(XY + YZ + ZX) = Var(XY) + Var(YZ) + Var(ZX)$

## 2010/02/25

### 數學藝術

Filed under: Fun,Report,University Mathematics — johnmayhk @ 12:33 下午

The image below,

Kuen’s Surface: A Meditation on Euclid, Lobachevsky, and Quantum Fields, by Richard Palais and Luc Benard of the University of California, Irvine, tied for first in the Illustration category in the 2009 Science and Engineering Visualization Challenge. The illustration shows sketches of Kuen’s surface and the expression that generates it. Palais said, “We wanted to talk about these equations in a way that non-mathematicians could understand. So we took a symbolic approach: The surface itself stands as a symbol for that equation." Benard used more than 200 hours of computer time to render the surface. (more…)

## 2010/02/07

### [FW][YouTube] Hong Kong, Gateway To China, 1938

Filed under: Life,Report — johnmayhk @ 5:12 下午