# Category Archives: Fun Stuff

## What’s an eigenface?

With the recent korean wave, we get to see lots of Korean pop, tv, movie stars in the media. But I found that I can never tell them apart. Especially, the ladies, tall, thin, beautiful but too homogenous. (Of course, … Continue reading

## Whither the golden ratio

According to this report from the Guardian, someone claims that the golden ratio pleases the eye because of scanning ratios, i.e. how fast the eye scans things horizontally versus vertically. The actual paper is supposed to be free access (with … Continue reading

## Collective Nouns for Mathematicians

A creative colleague got me started and I just can’t stop. Of course the most apt term would be “a set of mathematicians”. But how about others, according to their fields? Ignoring the obvious alliterative ones like “a set of … Continue reading

## 4 clicks to Mathematics

I learn this game from watching Tim Chartier’s video. (The original game was 5 clicks to Jesus but in this age of religious sensitivity … ) So this is the game, go to Wikipedia and click random article on the … Continue reading

## The Feynman Problem Solving Algorithm

according to here is this 1) Write down the problem 2) Think very hard 3) Write down the answer

## Math and Movies

A huge collection of video clips of movies and tv programmes that feature some mathematics. Some of which are a hoot. I especially love the one from Wizard of OZ where Scarecrow proclaims “the sum of the square root of … Continue reading

## Calligraphy

The Chinese character that appears on the left of the logo is a stylized version of 数 which means “to count” (as a verb) or a “number/value/sum” (as a noun). The Chinese word for mathematics is 数学, the art or … Continue reading

## Turing Doodle

I was supposed to wake up early before my two year old boy so that I could get some work done, but alas, I got distracted by the neat little Turing machine puzzle put up by the guys at google. … Continue reading

Posted in Fun Stuff, Number Theory, Quotes/People, Technology | 4 Comments

## Coincidences

I’ll be visiting China tomorrow and my mum kindly handed me a stack of RMB (China’s currency) that was left-over previously. I took a quick count and it totals exactly 1729 Yuan. What are the odds?

## It’s Pi Day today

A little creative tinkering yielded this mnemonic for $\pi$ Pi (apologies, latex died) to 15 places. “How I need a drink, alcoholic of course, after the heavy lectures involving Euclid’s algorithm” I’ve substituted “quantum mechanics” with “Euclid’s algorithm”, not exactly … Continue reading

## Homework

We have seen textbooks that only gives solutions to odd-numbered exercises. But have you seen a number theory text with the following exercises? 1) Prove that $x^3 + y^3 = z^3$ has no non-trivial solutions in integers. 2) Prove that … Continue reading

$\cos (3x) = 4\cos^3(x) -3 \cos(x)$ The way to remember it in Hokkien (a local dialect commonly spoken in Singapore, Taiwan and southern parts of China): Cor Sah ($1.30) = Si Cor Sah ($4.30) – Sah Cor ($3). You can … Continue reading Posted in Calculus/Analysis, Fun Stuff, Trigonometry | Leave a comment ## autologlyphs morphing maths with art by Henry Segerman. Cool stuff. I especially liked the mirror symmetry one. As usual, found via J. Cook. Posted in Fun Stuff, General | Leave a comment ## Bell Numbers defined as $\displaystyle B(n) = \sum_{k=0}^n \left\{ {n \atop k}\right\}$ counts the total number of ways to partition n distinct objects into disjoint subsets (or blocks) where $\displaystyle \left\{ {n \atop k}\right\}$ is the well known Stirling … Continue reading Posted in Combinatorics, Fun Stuff | Leave a comment ## pendulum waves Great video illustrating waves with 15 pendulums. Watch to the end to see the pendulums make one complete cycle. First saw this via john d cook. Posted in Fun Stuff, Physics, Teaching | Leave a comment ## Soap bubbles and current research That’s the title of Frank Morgan’s talk today. The main takeaway is how, (motivated?) students can be exposed to interesting problems and work on current research. For example, it has been known for almost 2000 years that the circle in … Continue reading Posted in Fun Stuff, Geometry/Topology, Teaching | Leave a comment ## A$23 million dollar book

A very interesting post. http://www.michaeleisen.org/blog/?p=358 It is not merely the astronomical price tag but the clever detective work that figured out what lead to the crazy price and is a good example of how algorithms can go wrong. Finally it … Continue reading