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564 posts tagged with Math.

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## "As you can probably imagine, this took some effort to make."

"The calculator itself is just over 250x200x100 blocks. It contains 2 6-digit BCD number selectors, 2 BCD-to-binary decoders, 3 binary-to-BCD decoders, 6 BCD adders and subtractors, a 20 bit (output) multiplier, 10 bit divider, a memory bank and additional circuitry for the graphing function." Yes, someone built a working scientific calculator, in Minecraft.

## So that's why they call 'em fractals!

## WHAT TIME IS IT?!

Do you like Adventure Time? (previously) Do you like 8-Bit Game intros? Then you'll like the 8-bit Adventure Time Video Game Intro.

## The Angel Problem

## Newton and Leibniz invent calculus.

There were ways to find the tangent to a curve, and the area under one, in an ad hoc manner before the birth of calculus. It was even known that these two were inverses of each other.

## Number A Day

## Morpion Solitaire

Morpion Solitaire is a very simple pencil-and-paper, line-drawing game for which the best possible score is not known! New records are still being set.

## What is it like to have an understanding of very advanced mathematics?

What is it like to have an understanding of very advanced mathematics? A naive Quora question gets a remarkably long, thorough answer from an anonymous respondent. The answer cites, among many other things, Tim Gowers's influential essay "The Two Cultures of Mathematics," about the tension between problem-solving and theory-building. Related: Terry Tao asks "Does one have to be a genius to do maths?" (Spoiler: he says no.)

## Monte Carlo

Conceptually talked about on MeFi previously, some basic Monte Carlo methods include the Inverse Transform Method (PDF) mentioned in the quoted paper, Acceptance-Rejection Sampling (PDFs 1,2), and integration with and without importance sampling (PDF).The year was 1945. Two earthshaking events took place: the successful test at Alamogordo and the building of the first electronic computer. Their combined impact was to modify qualitatively the nature of global interactions between Russia and the West. No less perturbative were the changes wrought in all of academic research and in applied science. On a less grand scale these events brought about a [renaissance] of a mathematical technique known to the old guard as statistical sampling; in its new surroundings and owing to its nature, there was no denying its new name of the Monte Carlo method (PDF).-N. Metropolis

## Two PDFs about PDFs

An "Exciting Guide to Probability Distributions" from the University of Oxford: part 1, part 2. (Two links to PDFs)

## I put in a quadratic and all I got was this dumb parabola

Google will now graph! Google Post description.
Now... examples! sin(x), exp(x), x^2+2x+1. We're not nearly done... [more inside]

## Breaking the Coppersmith-Winograd barrier

*For twenty years, the fastest known algorithm to multiply two n-by-n matrices, due to Coppersmith and Winograd, took a leisurely O(n^2.376) steps. Last year, though, buried deep in his PhD thesis, Andy Stothers discussed an improvement to O(n^2.374) steps. And today, Virginia Vassilevska Williams of Berkeley and Stanford, released a breakthrough paper [pdf] that improves the matrix-multiplication time to a lightning-fast O(n^2.37*[more inside]

**3**) steps. [via]## Eleven Equations True Computer Science Geeks Should (at Least Pretend to) Know

## Putting a style in your crimp

*Le Crimp*(mostly

*en français*) is a French collective that explores organic and abstract geometric [ I | II | III ] (PDFs) approaches to the art of origami. Read the white papers, browse the gallery or watch videos of artworks being made or being used in still-motion animations

## Pythagasaurus

Pythagasaurus is the fabled Tyrannosaurus practiced in the skills of trigonometry and long division. Apparently he knows all eight numbers. [Via]

## That which does not kill us makes us stronger

`> comp.basilisk - Frequently Asked Questions ::`

Almost everything about the incident at the Cambridge IV supercomputer facility where Berryman conducted his last experiments has been suppressed and classified as highly undesirable knowledge. It's generally believed that Berryman and most of the facility staff died. Subsequently, copies of basilisk B-1 leaked out. This image is famously known as the Parrot for its shape when blurred enough to allow safe viewing. B-1 remains the favorite choice of urban terrorists who use aerosols and stencils to spray basilisk images on walls by night. But others were at work on Berryman's speculations...[more inside]

**Is it just an urban legend that the first basilisk destroyed its creator?**Almost everything about the incident at the Cambridge IV supercomputer facility where Berryman conducted his last experiments has been suppressed and classified as highly undesirable knowledge. It's generally believed that Berryman and most of the facility staff died. Subsequently, copies of basilisk B-1 leaked out. This image is famously known as the Parrot for its shape when blurred enough to allow safe viewing. B-1 remains the favorite choice of urban terrorists who use aerosols and stencils to spray basilisk images on walls by night. But others were at work on Berryman's speculations...

## Knotty Problems

Science through yarn: Wooly Thoughts. The Home of Mathematical Knitting, including knitted klein bottles and hyperbolic planes. The Museum of Scientifically Accurate Fabric Brain Art (previously). Much, much, more on knitting, crochet and quilting used to visualize complex theories in topology, probability, chaos and fractals. [more inside]

## Bach is easy. If she brings him up, you just smile and you say: “Ahh, Bach.”

Bach as graph. -- An interactive visualization of the Cello Suite No. 1, Prelude.

## "Try not to think too hard."

## Machines of Paper and Wood

Building a Computer 1: Numerals -

*recently my kids have been asking me about how computers work. I like to give in-depth answers to such questions, so we set out on a quest to understand how they work...*Follow-up parts 2 3 4 5 6 7 8 9 10 11 12 13 14 15.## Wheels within wheels

The best known packings of equal circles within a circle. Best packings with 1-12 circles. Best packings with 49-60 circles. Best packings with 1093-1104 circles. Also, circles whose areas form a harmonic series. Circles in an isosceles right triangle. Or generate your own circle packings. (Background for beginners: circle packing. Background for experts: circle packing.)

## Corporate fraud / Benford's law

One way to measure corporate fraud is look at reported numbers and see if they follow Benford's law - number sets that are manipulated usually deviate from Benford's law. A recent analysis of all public companies over the past 50 years has shown a steady upward deviation, strongly suggesting there is more corporate fraud now than ever before (peaked in 2008). [more inside]

## Jewish Problems

This is a special collection of problems that were given to select applicants during oral entrance exams to the math department of Moscow State University. These problems were designed to prevent Jews and other undesirables from getting a passing grade. (via Hacker News)

## Museum of Mathematics, NYC

## C is still for Cookie, and that's good enough for me

Science! (autoplaying video) The 42nd season of "Sesame Street," which premiered today, will be including a few new educational categories for preschoolers in its usual mix of lessons and parodies: STEM skills — Science, Technology, Engineering and Mathematics. In addition to more scientifically accurate slapstick, characters will try experiments, build bridges and boats, launch rockets and think through problems that require trial and error, observation and data -- all problem areas for America's students. [more inside]

## Who's afraid of the seven times table?

Who's Afraid of the Seven Times Table?

*Ernst Kummer, one of the great mathematicians of the late 1800s, was hopeless at arithmetic. He was giving an advanced maths lecture and in the middle of a complicated calculation he needed to know what six times seven was. “Um ... six times seven is ... six times seven . . .” A student put up his hand: “41, Professor.” Kummer chalked 41 on the blackboard. “No, no, Professor!” shouted another. “It’s 44!” Kummer gave the students a quizzical look. “Come, come, gentlemen. It can’t be both. It must be either one or the other!”*[more inside]## G.H. Hardy reviews Principia Mathematica

"Perhaps twenty or thirty people in England may be expected to read this book." G.H. Hardy's review of Whitehead and Russell's

*Principia Mathematica*, published in the Times Literary Supplement 100 years ago last week. "The time has passed when a philosopher can afford to be ignorant of mathematics, and a little perseverance will be well rewarded. It will be something to learn how many of the spectres that have haunted philosophers modern mathematics has finally laid to rest."## Math for Art Students

Systems, networks, and strategies is a math course being developed and taught this semester at the San Francisco Art Institute, by Lee Worden. The course-outline-in-progress is online at the linked wiki, including links to course materials like "the two-in-one-out game," "Places to intervene in a system," on-line flocking simulations, and "street math in graffiti art."

## Echoes Reality

## It does one thing and it does it well.

iTex2Img converts LaTeX equations into images online.

## Donald in Mathmagic Land

Donald in Mathmagic Land is a 27-minute Donald Duck featurette released on June 26, 1959. As Walt Disney said, "We have recently explained mathematics in a film and in that way excited public interest in this very important subject." (Wiki)

## Math interview podcast

Strongly Connected Components is a podcast of interviews with mathematicians. Hear complexity theorist Scott Aaronson (of Shtetl-Optimized), Tom Henderson (of Punk Mathematics) algebraist Olga Holtz of UC-Berkeley, master combinatorist Richard Stanley of MIT, and many more.

## The Earth Is Flat (to a certain approximation)

Old Theories As Limits of New Ones -- Theoretical physicist, Lubos Motl, takes a brief tour through the history of physics, and explains the simple mathematical relationship of old theories to the theories that replace them.

## Growing a hyperdodecahedron

This short computer graphics animation

*presents the regular 120-cell: a four dimensional polytope composed of 120 dodecahedra and also known as the hyperdodecahedron or hecatonicosachoron.*[more inside]## Lisa Sauermann is the world's best high school math competitor

Lisa Sauermann of Germany has won her fourth gold medal at the International Mathematical Olympiad, making her the top performer in the high school math competition's history. The IMO has been has been run continuously since 1959. Sauermann scored a perfect 42 on this year's exam, the only contestant in the world to do so. Not impressed yet? Here are this year's problems: day 1 and day 2. Watch a bunch of mathematicians wrestle with problem 2 in real time at the polymath blog.

## Kill Math

Bret Victor on WorryDream The power to understand and predict the quantities of the world should not be restricted to those with a freakish knack for manipulating abstract symbols.
When most people speak of Math, what they have in mind is more its mechanism than its essence. This "Math" consists of assigning meaning to a set of symbols, blindly shuffling around these symbols according to arcane rules, and then interpreting a meaning from the shuffled result. The process is not unlike casting lots.

## Beaded Beads

Beaded Polyhedra ❂ More beadwork (mathematical and otherwise) by Gwen Fisher ❂ Still more beadwork galleries at beAdinfinitum ❂ Three-dimensional finite point groups and the symmetry of beaded beads [pdf - some algebra, but lots of illustrations]

## Then you wouldn't have to say "QED", 'cause I'd already know

A thread full of proofs without words at MathOverflow and quite a lot more of them courtesy of Google Books.

## Vermont 1, Rest of USA 0

## The Cartoon Guide to Life, the Universe, and Everything

Larry Gonick is a veteran American cartoonist best known for his delightful comic-book guides to science and history, many of which have previews online. Chief among them is his long-running

*Cartoon History of the Universe*(later*The Cartoon History of the Modern World*), a sprawling multi-volume opus documenting everything from the Big Bang to the Bush administration. Published over the course of three decades, it takes a truly global view -- its time-traveling Professor thoroughly explores not only familiar topics like Rome and World War II but the oft-neglected stories of Asia and Africa, blending caricature and myth with careful scholarship (cited by fun illustrated bibliographies) and tackling even the most obscure events with intelligence and wit. This savvy satire carried over to Gonick's Zinn-by-way-of-*Pogo*chronicle*The Cartoon History of the United States*, along with a bevy of*Cartoon Guides*to other topics, including*Genetics, Computer Science, Chemistry, Physics, Statistics, The Environment*, and (yes!)*Sex*. Gonick has also maintained a few sideprojects, such as a webcomic look at Chinese invention, assorted math comics (previously), the*Muse*magazine mainstay*Kokopelli & Co.*(featuring the shenanigans of his "New Muses"), and more. See also these lengthy interview snippets, linked previously. Want more? Amazon links to the complete oeuvre inside! [more inside]## Odlyzko on electronic publishing, 1996

"As recently as a year ago, there were many publishers, librarians, and scholars who thought that electronic publishing was just a passing fad." In 1996, the number theorist Andrew Odlyzko, a pioneer in the development of "experimental mathematics" via large-scale computation, wrote a article, prescient in many respects, about the effect the Internet would have on the economics of scholarly publication, and on commerce more generally.

## "so you can imagine, here I was, an analyst at a hedge fund; it was very strange for me do to something of social value"

Salman Khan: The Messiah of Math - "His free website, dubbed the Khan Academy, may well be the most popular educational site in the world. Last month about 2 million students visited. MIT's OpenCourseWare site, by comparison, has been around since 2001 and averages 1 million visits each month... [more inside]

## Is this x defined? Is F continuous?

Calculus Rhapsody Like it says on the tin.

## The Discrete Charm of the 1, 1, 2, 3, 5, 8, ...

Do you like integer sequences? Do you like poking around in the The On-Line Encyclopedia of Integer Sequences? Do you think, whoa, wait, okay, actually I like integer sequences but the OEIS is a goddam intractable maze of numbers? Do you think, man, what I wish is that someone would make an accessible blog that discusses some of the interesting entries in the OEIS for the casual fan of integer sequences? Well, that's an amazing coincidence; you should take a look at The On-Line

*Blog*of Integer Sequences, by our very own Plutor.## Well, just take n=1...right?

In the afternoon of May 4, 1971, in the Stouffer's Somerset Inn in Shaker Heights, Ohio, Steve Cook presented his STOC paper proving that Satisfiability is NP-complete and Tautology is NP-hard. [more inside]

## Is teacher evaluation statistical voodoo?

"Value-added modeling is promoted because it has the right pedigree -- because it is based on "sophisticated mathematics." As a consequence, mathematics that ought to be used to illuminate ends up being used to intimidate." John Ewing, president of Math for America and former executive director of the American Mathematical Society, criticizes the "value-added modeling" approach used as a proxy for teacher quality, most famously in a Los Angeles Times story that called out low-scoring teachers by name. A Brookings Institution paper says value-added modeling is flawed but the best measure we have of teacher value, arguing that the metric's wide fluctuations from year to year are no worse than those of batting averages in baseball. (Though the weakness of that correlation is mostly a BABIP issue.) Can we assign a numerical value to teacher quality? If so, how?

## Nature Special Issue on the Future of the PhD

## My cell phone connects me with my friends and also calculates logarithms

Are graphical calculators pointless? Graphical calculators are required by many college-level math courses, but they don't perform as well as mobile phones. Pedagogically, they may be less useful than a slide rule. [more inside]

## True art is irrational.

This is what pi sounds like. At least, that's one person's interpretation. There are certainly plenty of others, including touchtone pi, hammered dulcimer pi, violin pi, smooth techno pi, crazy awesome pi, vaguely unsettling pi (sounds best with headphones), and lots of piano pi. Pi has even done a duet with its buddy

(pi as music previously on metafilter)

*e*. Nothing here that tickles your fancy? Think you could do better? Why not make your own pi song? Hell, make two! If you're having trouble remembering all those pesky digits, don't worry: there's a song for that, too.(pi as music previously on metafilter)

## Talking fast and making cool videos does not mean learning is happening

So you're me and you're in math class and you're learning about graph theory, a subject too interesting to be included in most grade school's curricula so maybe you're in some special program or maybe you're in college and were somehow not scarred for life by your grade school math teachers. [more inside]