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David Joyner
Works at USNA
Attended Georgia Institute of Technology
Lives in arnold, md
8,327 followers|543,153 views
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David Joyner

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Just saw this nice new blog on math education.
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David Joyner

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Interesting copyright news
Attorneys for suing filmmakers uncover a blurry version of an 88-year-old book in the files of Warner/Chappell. That leads to another serendipitous discovery.
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David Joyner

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Very simple card trick, thanks to futilitycloset.com.

"Arrange cards with values ace through 9 in a row, in counting order, with the ace on the left.
Take up a card from one end of the row — left or right, your choice.
Do this twice more, each time taking up the leftmost or the rightmost card in the remaining row.
When you have three cards, add their values and divide the total by six. Count the cards that remain on the table from left to right.
The card in the nth position will be the 4."

Is there is a generalization to other numbers of cards?

source: http://www.futilitycloset.com/2015/07/16/destiny-2/
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+Joal Heagney Cool, thanks!
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David Joyner

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Very easy mate-in-2 due to Sam Loyd, thanks to futilitycloset.com:
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David Joyner

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Crazy wild math fact, care of the futilitycloset.com, below.

Here is Sagemath code:

a = 999999999999999999999998999999999999999999999999
RR = RealField(prec=500,rnd="RNDU")
L = [fibonacci(n)*1.0*10^(-n*24-24) for n in range(15)]
RR(sum(L)*a)

which outputs 

1.000000000000000000000000000000000000000000000...
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David Joyner

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Saw this first on slashdot. Quoting:

"...after just four weeks on a high-fat or a high-sugar diet, the performance of mice on various tests of mental and physical function began to drop, compared to animals on a normal diet. One of the most pronounced changes was in what researchers call cognitive flexibility."
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Cognitive is not the only determination of Water maze testing score. Fat animals usually earn bad scores due to lower physical performance. Four weeks high fat or high surge diet should result in fat animals.
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Elsevier cares about scientific research exactly as much as they their ability to turn it into green folding paper for their wallets.
Statement against Elsevier's sharing policy. Organizations around the world denounce Elsevier's new policy that impedes open access and sharing. On April 30, 2015, Elsevier announced a new sharing and hosting policy for Elsevier journal articles. This policy represents a significant obstacle to ...
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Have him in circles
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David Joyner

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Nice short intro to the combinatorial Kirkman schoolgirl problem, care of the futilitycloset.com:
“Fifteen young ladies in a school walk out three abreast for seven days in succession: it is required to arrange them daily, so that no two shall walk twice abreast.” The Rev. Thomas Penyngton Kirkman posed this query innocently in The Lady’s and Gentleman’s Diary in 1850. It’s trickier than it looks — though seven …
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David Joyner

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Just saw this one-liner: Time flies like an arrow; fruit flies like a banana.
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That's a really old one that came up a lot back in the heyday of artifical intelligence work. How could a software program parse that?
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I'm no expert but decided to write a very basic post on formatting anyway, mostly for my own benefit.
For beginners only.
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Script formatting basics
This is not a post on story structure or movie analysis. This is simply an introduction to the basics of movie script formatting, intended strictly for the beginner. To be more precise, we focus on feature length narrative spec scripts. In other words, a mo...
This is not a post on story structure or movie analysis. This is simply an introduction to the basics of movie script formatting, intended strictly for the beginner. To be more precise, we focus on feature length narrative sp...
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It's up now.
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Have him in circles
8,327 people
Shawn Scientifica's profile photo
Richar Benitez's profile photo
Manuel Valcarcel's profile photo
John Chumack's profile photo
Richard PRESSANTI's profile photo
antonio alfaro's profile photo
Raphael Magalhães's profile photo
Gerson Lage's profile photo
Ptk Ventures LLC's profile photo
Education
  • Georgia Institute of Technology
    math
  • University of Maryland, College Park
    math
Basic Information
Gender
Male
Story
Tagline
math, writing, tech, edu, ...
Introduction
Enjoy tinkering with mathematics, writing, Sage (www.sagemath.org), video, chess, and photography. Interested in math education-related and open-source software issues.
Bragging rights
have managed to stay off facebook
Work
Occupation
math prof
Employment
  • USNA
    math prof, present
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
arnold, md
Previously
mountain view, ca - kent, wa - decatur, ga - princeton, nj - san diego, ca
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I have used All for the Pet for years and never once had rude service. The store doesn't even open until 9am and Lisa often comes in early to help out people who want to drop off their pet before going to work. I think she does a good job with my pets and her prices are reasonable.
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reviewed a year ago
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