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Xah Math Blog

Xah's Math Blog Archive 2013-01 – 2013-02
2013-02-26

a blog by Glenn Wilcox with lots beautiful math-related pictures generated in Rhinoceros 3D @ http://www.generativedesigncomputing.net/

2013-02-20

Teacup Recursion Animation

2013-02-17

O, math, my true love, but how i have alienated thee, and you being quite difficult.

2013-02-15

“the right way to answer true and false questions”
2013-02-12

math rubiks cube tattoo
2013-02-09

Microwave Arithmetic
on a microwave, you press 2 0 0 for 120 seconds, but 1 2 0 for 80 seconds, yet 9 0 for 90 seconds.

can you establish the rules for microwave number system or microwave arithmetic?

2013-02-07

linear algebra comics
“线性代数”. Linear algebra tutorial, in the form of comics, in Japan. How wonderful.
thx to weizhoupan

What is Technical Drawing, Descriptive Geometry, Projective Geometry, Linear Algebra
Vector Normalize Function in Mathematica, APL, Haskell, Ruby, Python, Perl, Lisp, JavaScript, Java, …
Intro to POV-Ray and 3D Geometry Programing
The Codification of Mathematics
2013-02-04

by C. Burke (used with permission)
2013-02-03

Doyle spiral + Mobius transformation
“Doyle spiral + Mobius transform” by fdecomite image source on 2008-04-04 .
2800×2100
©cc
can you identify what function is this?

it looks like a Mobius Transformation. But what's the exact parameters and what's the input image? (assume each ball is just a dot.)

Mobius Transformation is a function of the form `f[z] = (a z + b) / (c z + d)`

and `a d − b c ≠ 0`

. The variables are all complex numbers.

For a simple geometric explanation of complex numbers, see:
Isometries: Translation, Rotation, Reflection and
Mandelbrot Set Explained (no complex number needed) .

2013-01-14

recursion bonanza: Teacup Recursion Animation

2013-01-09

5-Point Conics (needs Java installed.)

2013-01-08

Logic Based Human Language: Lojban
xkcd comics on lojban.
(http://xkcd.com/191/ )
Lojban is a constructed language, design based on predicate logic. Some tutorial here, with voice recording: Xah's lojban Tutorial .

2013-01-07

Alice in Wonderland, Zero-sum game
“The more there is of mine, the less there is of yours.”

from Wonderland: Chapter 9: The Mock Turtle's Story

That's the concept of Zero-sum game. However, in real world, most things isn't zero-sum game. Both parties actually benefit. ⁖ when you give something you no longer want to someone, a value is created “out of nothing”.

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