# Quod Erat Demonstrandum

## 2012/04/30

### 由功課無聊談起

Filed under: Fun — johnmayhk @ 5:52 上午

## 2012/04/27

### .

Filed under: Uncategorized — johnmayhk @ 12:03 下午

### [FW] golden balls. the weirdest split or steal ever!

Filed under: Fun — johnmayhk @ 4:53 上午

## 2012/04/26

### [FW] Top N Facts about the Klein Bottle

Filed under: Fun — johnmayhk @ 9:07 上午

## 2012/04/25

### [TED] The Connectome

Filed under: Fun — johnmayhk @ 11:07 上午

Reading the Book of Memory: Sparse Sampling versus Dense Mapping of Connectomes
http://hebb.mit.edu/people/seung/papers/Seung_2009_Neuron_withxtrapg.pdf

## 2012/04/24

### 某次中四測驗的 1 分題目

Filed under: NSS — johnmayhk @ 11:08 上午
Tags:

It is given that $x^5+81x^4+2590x^3+40830x^2+317089x+969969=0$ has five distinct real roots. Which of the following graph is the best representation of the graph of $y=x^5+81x^4+2590x^3+40830x^2+317089x+969969$? Explain your answer.

## 2012/04/23

### 至愛幾何

Filed under: Fun — johnmayhk @ 5:14 上午

## 2012/04/22

### 答一題

Filed under: NSS — johnmayhk @ 12:14 上午

Solve

$2x^4-x^3+3x^2-x+2=0$

Solution

(Trick: (more…)

## 2012/04/21

### 圓錐截線切線

Filed under: NSS,Teaching — johnmayhk @ 2:40 下午

Core Mathematics 習題：

Let $C:x^2+y^2-6x+2y-15=0$. Show that $P(6,3)$ lies on $C$ and find the equation of the tangent to $C$ at $P$.

Let $L: y-3=m(x-6) \Rightarrow y=mx+(3-6m)$ (more…)

## 2012/04/16

### 分數微積分

Filed under: Fun — johnmayhk @ 7:47 上午

## 2012/04/15

### 答兩題

Filed under: NSS — johnmayhk @ 3:58 下午

（一）關於三角形邊比和面積比的問題，通常分兩類：

1. same altitude（等高）（兩個三角形不一定是相似），有

Area of $\Delta ABC$ : Area of $\Delta ACD$ = $BC$ : $CD$

2. similar（相似）

Area of $\Delta EFG$ : Area of $\Delta HIJ$ = $(FG:IJ)^2$

## 2012/04/07

### 數學的詩歌舞

Filed under: Fun — johnmayhk @ 2:48 上午

(more…)

## 2012/04/06

### [Video] To Infinity and Beyond – Horizon – BBC

Filed under: Fun — johnmayhk @ 12:43 上午

## 2012/04/05

### [FW] Petits contes mathematiques : le theoreme de Pythagore

Filed under: Fun,Junior Form Mathematics — johnmayhk @ 11:37 上午

Click click 看：

## 2012/04/04

### [FW] PBS Nova – Fractals – Hunting the Hidden Dimension

Filed under: Fun — johnmayhk @ 10:11 上午

Hunting the Hidden “Dimension" 已是一個很值得玩味的片名！除了反映碎形幾何的非正整數「維度」，也介紹了一些碎形幾何鮮為人知（人：指非數學本科的一般大眾）的應用「向度」，比如在手機、醫學甚至全球暖化的研究上，碎形幾何也扮演關鍵角色。