23 January 2011

How to validate a credit card number with your head using a checksum as presented on mint.com's blog. Take the above number (or any credit card number). And double every other digit from the right. Add these new digits to undoubled ones. All double digit numbers are added as a sum of their digits, so 14 becomes 1+4. If the final sum is divisible by 10, the number is invalid or fake. Try it and see.

How to validate a credit card number (click for full pic)

[via:Viralliset Linkit]

22 April 2010

Man spends 3 years maxing out a perfectly optimized SimCity 3000 city #

[via:Abraham Williams/RT]

16 November 2009

mandelbulb 3d mandelbrot fractal shell life skytopia

Mandelbulb: The Unravelling of the Real 3D Mandelbrot Fractal

[via:Nelg]

25 October 2009

Math Overflow, a Questions and Answers site for math problems

Implemented using the platform of Stack Overflow, a Q&A board for programming topics. Beats any old-type forums or wiki sites, they have among other things, an addicting reputation and badge system inspired by Xbox Live.

[via:Spolsky]

15 August 2009

“When Zombies Attack!: Mathematical Modelling of an Outbreak of Zombie Infection,” by Philip Munz, Ioan Hudea, Joe Imad and Robert J, Smith.

In “Infectious Disease Modelling Research Progress,” eds. J.M. Tchuenche and C. Chiyaka, Nova Science Publishers, Inc. pp. 133-150, 2009.

Wired provides a summary.

[via:Slashdot]

11 June 2009

Wolfram Alpha Cannabis Function

Sweet Wolfram Alpha Leaf

The magic word is PolarPlot[(1 + 0.9 Cos[8 t]) (1 + 0.1 Cos[24 t]) (0.9 + 0.05 Cos[200 t]) (1 + Sin[t]), {t, -Pi, Pi}.

[via:saasta.fi]

24 August 2008

Mathematicians create videos that help in visualizing four-dimensional objects

The article has a broken link to dimensions-math.org.

[via:Slashdot]

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