# Quod Erat Demonstrandum

## 2008/10/25

### 全球暖化

Filed under: Teaching — johnmayhk @ 7:32 下午
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### 中二數學課：恆等式

Filed under: Junior Form Mathematics,Teaching — johnmayhk @ 6:40 下午
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### 太太的新工作

Filed under: Family,School Activities — johnmayhk @ 6:21 下午
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## 2008/10/22

### Integrate polynomial of degree less than 4

Filed under: Additional / Applied Mathematics — johnmayhk @ 8:30 下午
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To find the definite integral of a polynomial of degree less than 4, we can use the following formula.

$\int_a^b p(x)dx = \frac{b - a}{6}[p(a) + 4p(\frac{a+b}{2}) + p(b)]$

e.g.

$\int_2^4 (x-2)(x-4)(x-7)dx = \frac{4-2}{6}[0 + 4(3-2)(3-4)(3-7) + 0] = \frac{16}{3}$

Nothing special, it is just something about Simpson’s rule.

### 中二數學堂：零的零次方

Filed under: Junior Form Mathematics — johnmayhk @ 1:01 下午
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（虛擬人物）同學丁：「答案是 0，因為 0 的任何次方都是 0。」 (more…)

## 2008/10/21

### 用 EXCEL 玩 Matrix

Filed under: Pure Mathematics — johnmayhk @ 5:17 下午
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TA 哥哥在教員室玩完魔術 （可能是 rock sir 教的魔術），主動教我用 EXCEL 玩 matrix，我學了，教大家。修 pure mathematics 的同學，留意。

1. 行列式（determinant）

$\left|\begin{array}{rcl}1&2\\3&5\end{array}\right|$，我們可在 EXCEL 工作表輸入

## 2008/10/18

### 從數學奧林匹克到東拉西扯：一個數學老師的競賽路

Filed under: Report,Teaching — johnmayhk @ 3:19 下午
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## 2008/10/17

### 不能秒殺的提問

1. 誰發明 $_nC_r$ 這個符號？
2. 畢氏數組中是否必然存在 3 或 5 的倍數？ (more…)

## 2008/10/15

### Assuming step in mathematical induction

Just share a minor point in the presentation of M.I.

To prove that a proposition P(n) is true for all positive integers n by using M.I.

We need ‘4’ steps, namely (more…)

## 2008/10/14

### 回茵茵老師

Filed under: Teaching — johnmayhk @ 11:53 下午

## 2008/10/11

### 新數學教師研習課程

Filed under: Report,School Activities,Teaching — johnmayhk @ 3:24 下午
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## 2008/10/10

### Say something about series in Applied Mathematics (II)

Filed under: Additional / Applied Mathematics,HKALE — johnmayhk @ 4:53 下午
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Here is just a typical question in AL Applied Mathematics (II).

For natural numbers $m, n$ ($m \ge n$).

Let $f(x) = x^ne^x$, evaluate $f^{(m)}(0)$. (more…)

(more…)

## 2008/10/03

### 蝗蟲 の Joy

Filed under: Fun,School Activities — johnmayhk @ 3:30 下午