Math

• 
  Google News: Math

• Judge nixes 'math game' - Winnipeg Sun

  21 Nov 2009 | 3:00 am

  Judge nixes 'math game'Winnipeg Sun"This would amount to nothing more than a math game and would bring the administration of justice into disrepute," Martin said. Scott remains a high risk to Judge ignores, tops joint recommendation for rapist's sentenceWinnipeg Free Pressall 3 news articles »

• Advanced math a welcome challenge - Times and Transcript

  21 Nov 2009 | 2:00 am

  Kingwood NewsAdvanced math a welcome challengeTimes and TranscriptIn one of my columns earlier this year, I mentioned that I wasn't taking part in the math assessment that all Grade 8s have to take at the end of June each Winners Announced for Kingwood.com & Atascocita.com Essay ContestKingwood Newsall 2 news articles »

• The scary new math of warming - Toronto Star

  21 Nov 2009 | 1:36 am

  The scary new math of warmingToronto StarI f new environmental campaigns take hold, you'll hear a lot about two numbers during the next few months.

• Don't delay reckoning on science, math norms - The Spokesman Review

  21 Nov 2009 | 12:23 am

  OregonLive.comDon't delay reckoning on science, math normsThe Spokesman ReviewHowever, math and science requirements were postponed, because it became obvious that a high percentage of students would not measure up. Supt. Dorn calls for changes to math, science graduation requirementsNisqually Valley NewsState School Super Calls for Delay on Math and Science RequirementsPubliCola (blog)State schools chief Randy Dorn blinks on math and science requirementsSeattle TimesOregonLive.com -KPLU -TheNewsTribune.comall 70 news articles »

• Elementary math update spurs more debate - Frederick News Post (subscription)

  20 Nov 2009 | 11:03 pm

  Elementary math update spurs more debateFrederick News Post (subscription)Debate continues over Investigations in Number, Data and Space, the math resource being used at the elementary level in Frederick County and more »

• 
  Topix: Math

• The teeth are gone, let's hope wisdom isn't

  21 Nov 2009 | 4:40 am

  I was assured many things before my operation to have my wisdom teeth removed. Among them, the promises that I would be blissfully stoned for the entire day following the procedure, that I would get to miss up to five glorious days of school and, most crucially, that I would get to snack on innumerable soft treats for a week, including such ...

• As You See It: Nov. 21, 2009

  21 Nov 2009 | 4:35 am

  Your Nov. 16 article entitled "Stimulus adds jobs, but will they last?" by Kurtis Alexander was a good start in exposing Sentinel readers to the fraud of the so-called jobs created by the Obama administration.

• Cash better than rate cut - Fitch

  21 Nov 2009 | 4:34 am

  The provincial government is making a mistake by slashing power rates for New Brunswick industry instead of taking cash from Hydro-Quebec and paying down the provincial debt, says Opposition energy critic Bruce Fitch.

• Stuyvesant arsonist caught on video: officials

  21 Nov 2009 | 4:30 am

  Mohammed Hassan, 16, is charged with starting two fires in Stuyvesant High School after he was caught on tape, but his father insists his son is being framed by the school's principal.

• Can New Bing Features Best Google?

  21 Nov 2009 | 4:27 am

  Microsoft is adding to Bing's search features, loading up Bing with map enhancements, video integration and the use of Wolfram Alpha search results.

• 
  ScienceDaily: Mathematics News

• Active hearing process in mosquitoes

  21 Nov 2009 | 2:00 am

  A mathematical model has explained some of the remarkable features of mosquito hearing. In particular, the male can hear the faintest beats of the female's wings and yet is not deafened by loud noises.

• Examining mathematical abilities in children with fetal alcohol spectrum disorder

  20 Nov 2009 | 11:00 am

  Children with fetal alcohol spectrum disorder (FASD) have a number of cognitive deficits. Mathematical ability seems particularly damaged in children with FASD. A new study supports the importance of the left parietal area for mathematical abilities in children with FASD.

• Immediate, aggressive spending on HIV/AIDS could end epidemic

  18 Nov 2009 | 5:00 pm

  Money available to treat HIV/AIDS is sufficient to end the epidemic globally, but only if we act immediately to control the spread of the disease, according to new research. This approach defies conventional thinking, which recommends gradual spending over 15-20 years. The study was based on a mathematical model developed by mathematicians and biologists, who recently earned acclaim for a study on how best to handle a planetary invasion by zombies.

• Facial biometrics system capable of creating a facial 'DNA'

  16 Nov 2009 | 2:00 am

  Research into techniques of facial biometrics, carried out by scientists in Spain, has resulted in a system that is able to recognize the facial "DNA" of every individual by determining his/her most noteworthy facial traits, with a of 95% rate of precision.

• Underground Power Lines That Bypass Monuments In Cities

  12 Nov 2009 | 2:00 am

  Mathematicians have created a method to design underground lines whereby a city's historical buildings are unaffected.

• 
  Scientific American - Math

• Ask the Brains: Are our Brains Constantly Making Subconscious Calculations?

  17 Nov 2009 | 6:00 am

  Is it true that when we drive, walk or reach for something our brain performs calculations? Is this ability learned or innate? --Helena Larks, San Francisco [More]

• How Hard Has the Recession Hit Environmental Activist Groups?

  10 Nov 2009 | 9:00 pm

  Dear EarthTalk: Is it true that environmental non-profits have been hit hard by the economic downturn, and has this had an impact on their effectiveness? -- Bridget W., Bainbridge Island, WA [More]

• Happy (2 5 x 3 - 1)th birthday to Martin Gardner

  21 Oct 2009 | 9:45 am

  Longtime Scientific American columnist Martin Gardner turns 95 Wednesday, and a profile in Tuesday's New York Times honors the mathematical proselytizer who, tireless as ever, marks the milestone himself with the publication of a new book. [More]

• Mathematician sees a Yankees-Dodgers World Series, but don't pop that bubbly yet

  15 Oct 2009 | 2:35 pm

  The National League Championship Series gets under way this evening when the Los Angeles Dodgers host the Philadelphia Phillies, and tomorrow the American League follows suit as the Los Angeles Angels of Anaheim visit the New York Yankees. [More]

• Bird Moves: Dancing with the Starlings

  15 Oct 2009 | 8:00 am

  Researchers have long assumed that humans were the only animals that could dance--even our close primate relatives cannot keep a steady beat or be taught to move to a rhythm. But new evidence shows that birds can dance, revealing that the mysterious ability could be a by-product of vocal learning.Aniruddh Patel of the Neurosciences Institute, Adena Schachner of Harvard University and their colleagues studied several birds, among them a cockatoo that dances to the Backstreet Boys’ “Everybody.” When Patel sped up or slowed down the song, the bird adjusted its moves to match…

• 
  NYT: Mathematics

• Are Metrics Blinding Our Perception?

  20 Nov 2009 | 9:00 pm

  Welcome to the Age of Metrics - or to the End of Instinct.

• 1,000,000,000,000

  20 Nov 2009 | 9:00 pm

  The democratization of trillion has become a cause of confusion; the vastness still seems elusive.

• Steps Taken to Reduce Mistakes on 911 Fire Calls

  20 Nov 2009 | 9:00 pm

  Recent mix-ups that sent firefighters to the wrong addresses in New York led to new procedures.

• For Decades, Puzzling People With Mathematics

  19 Oct 2009 | 9:00 pm

  Martin Gardner is the world’s best-known recreational mathematician, and has probably introduced more people to the joys of math than anyone in history.

• Sluggish Results Seen in Math Scores

  14 Oct 2009 | 9:00 pm

  Test results suggest that the nation will not come close to the goal of bringing all children to proficiency by 2014.

• 
  MathNotations

• The Return of the WarmUp Challenges!

  Dave Marain

  15 Nov 2009 | 6:53 am

  Just when you thought that MathNotations is on permanent hiatus or in hibernation, here are a couple of WarmUps/Problems of the Day/Test Prep/Challenges/// to consider for your students.  Actually, I'm embarking on a new venture - an online tutoring website with live audio and video for OneOnOne math tutoring for Grades 6-14 (through Calculus II). In addition, I'm also working on setting up a small group (5-10 students) online SAT or ACT Course grouped by ability (a 600-800 SAT group, a 450-600 group, etc.).  If you're interested in getting more information about these before the…

• THE OPEN-ENDED CONTEST PROBLEM AND SOLUTIONS

  Dave Marain

  4 Nov 2009 | 3:04 am

  As promised, here is the open-ended, rubric-based, holistically scored, performance-assessed, student-constructed first problem from MathNotation's Third Contest:1. A primitive Pythagorean triple is defined as an ordered triple of positive integers (a,b,c) in which a2 + b2 = c2 and the greatest common factor (divisor) of a, b and c is 1. If (a,b,c) form such a triple, explain why c cannot be an even integer.Comments(a) The content here is number theory. Is some of this covered in your district's middle school curriculum or beyond? More importantly, at what point do students begin to formulate…

• RESULTS OF THIRD MATHNOTATIONS CONTEST and OTHER NEWS...

  Dave Marain

  3 Nov 2009 | 6:00 am

  FINALLY -- THE RESULTS ARE IN!!I apologize for the delay in getting these results out. The participating schools have all been notified.NOTE: If any participating school did not receive an email from me, the advisor should email me. Also, if I misspelled anyone's name pls let me know and I'll correct it immediately!INITIAL COMMENTS ON CONTEST, ETC...MEAN SCORE: 5.6 PTS OUT OF 12TOPICS INCLUDED Number Theory, Geometric Sequences, Function Notation, Geometry, Discrete Math, Quadratic Functions, and Absolute Value Inequalities (advanced level)Twenty schools registered from around the world, but…

• A Rant, An Update and Model Problems for You

  Dave Marain

  12 Oct 2009 | 3:42 am

  And the seasons they go round and round And the painted ponies go up and down We're captive on the carousel of time We can't return we can only look behind From where we came And go round and round and round In the circle game...Oh, how I love Joni Mitchell's lyrics made famous by the inimitable Buffy Sainte-marie. Oh, how The Circle Game lyrics above describe my feelings about the state of U.S. math education. I feel I've been on this carousel forever. But I do believe that all is not hopeless. I do see promise out there despite all the forces resisting the changes needed to improve our…

• Another Sample Contest Problem - Counting...

  Dave Marain

  5 Oct 2009 | 3:29 am

  There is still time to register for the upcoming MathNotations Third Online Math Team Contest, which should be administered on one of the days from Mon October 12th through Fri October 16th in a 45-minute time period.Registration could not be easier this time around. Just email me at dmarain "at" "gamil dot com" and include your full name, title, name and full address of your school (indicate if Middle or Secondary School).Be sure to include THIRD MATHNOTATIONS ONLINE CONTEST in the subject/title of the email. I will accept registrations up to Fri October 9th (exceptions can always be…

• 
  Math-U-See Blog

• Math-U-Do & Best Homework Picture Ever!

  ethan

  11 Nov 2009 | 7:54 am

  I was browsing the blogs the other day and saw this picture of Joel doing his math homework. He reminded me of myself when I was his age. My mom would tell me to run around the house repeatedly and time me, I kept trying to beat my fastest time while she was just draining some of my energy. My mom also put up a chalkboard and had me write standing up so I could be moving, as sitting still wasn’t a viable option. Excerpts from the Kent Kim & Kids Blog. Our bouncy, baby Joel grew up and as his Kindergarten teacher/Mother I’ve recently discovered that Joel seems to be kinesthetic…

• Steve Interviewed on Prime Time America

  ethan

  21 Oct 2009 | 11:29 am

  Steve was recently interviewed by Paul Butler on Moody Radio’s “Prime Time America” You can listen to Steve’s segment “kids and math” on Paul Butler’s blog. Despite years of federally funded education initiatives, a recent study by the NAEP reports that our children are still performing poorly in basic mathematics. Steve Demme is the Founder, President and Author of Math U See. He helps us understand why our kids are struggling and what we can do about it. In this feature, Mr. Demme mentions the first step in helping our children improve in math is to…

• Math-U-See Student Wins Google SketchUp Contest

  ethan

  13 Oct 2009 | 2:11 pm

  We recently received this email from proud parent and wanted to share it with you. Dear Steve, one of your students - Matthew Notaro - won the 2009 Google SketchUp Kid’s Digital Design Contest and was honored by the Howe brothers - Popular Science’s 2009 Inventors/Invention of the year. Your Math program was a direct result to his success. In 7th grade he got so bogged down by Saxon Math’s overkill review and drill he spent over 2 hours a day per lesson and slid farther and farther behind. We finally listened to some friends and ordered your intro DVD. Math U See’s…

• I Love U

  ethan

  1 Oct 2009 | 12:28 pm

  A happy mom sent me this the other day and I just had to share it. This is Cole. He is my 11 year old (6th grade) son. For 4 years we have stressed, cried, and begged the school to help figure out what was going on with him. They kept saying ADHD (surprise!) But after being tested twice he still wasn’t diagnosed ADHA. I started pushing for him to be tested for dyslexia. But, Ky doesn’t do that. I finally had him tested myself and guess what? Momma was right! But KY doesn’t recognize dyslexia as a LD so rather than fight the system I pulled Cole out and began homeschooling.

• Great Pre Calculus Testimony

  ethan

  26 Aug 2009 | 2:00 pm

  I was browsing a forum today and someone asked the question “Does home schooling affect a student’s chances of getting into college?” here is one of the responses. Home schooling most definitely affects a student’s chances of getting into a good university. In most cases, it improves their chances. Most home school materials and curricula are designed for use by the parent who is not an expert in every subject. I’m taking Pre Calculus this year, and my mom barely got through high school algebra. We use a home school math curriculum called Math U See. It is a…

• 
  Wild About Math

• History and trajectory of Mathematica

  Sol

  6 Nov 2009 | 5:24 pm

  Today’s Wolfram Alpha Blog is the first in a series of videos and transcripts from Stephen Wolfram’s keynote address at the International Mathematica User Conference 2009. From the Wolfram Blog entry: Future Mathematica features, new directions for Wolfram|Alpha, and how the two Wolfram technologies will be integrated were highlights of Stephen Wolfram’s keynote address at the International Mathematica User Conference 2009. This first video gives a quick history of Mathematica from its roots going back to 1981. I’m looking forward to hints about future features.

• MMM #38: We have a winner!

  Sol

  30 Oct 2009 | 10:31 am

  Random.org selected Ken Lareau as the winner for MMM #38. Congratulations, Ken! Here’s what the problem was: Prove or disprove: The product of any four consecutive integers is always one less than a perfect square. Don’t assume the integers are all positive. Here’s Ken’s solution: The above conjecture is true. The domain can be simplified a bit by noting two things: 1) If there are both positive and negative integers in the product, then since they’re consecutive, 0 has to be present, meaning the product is 0, which is one less than 1, a perfect square. 2) If all the…

• How much would you pay for a 146 year old Math book?

  Sol

  29 Oct 2009 | 4:51 pm

  Every now and then I like to buy old Math books. I buy them on Ebay. Most of the books I buy are from the early 1900’s or the tail end of the 1800’s. Yesterday, I happened upon this book: Yes, it’s from 1863. Yes, I paid $6.50 for it and there was no shipping charge. What’s the book about? Beats me. I’m not quite sure what Analytical Arithmetic Antique College Math is. If you think you know, leave a comment. What condition is the book in? Dunno but for six and a half bucks I’m not complaining! ShareThis

• ‘Dismantling the calculus pyramid’ gets ton of views

  Sol

  29 Oct 2009 | 7:52 am

  A couple of days ago I posted a very brief article, Dismantling the calculus pyramid. The post has been seen 2,746 times, thanks mostly to being noticed by ‘timwiseman’ who posted a link to the article at Y Combinator Hacker News. The posting at Y Combinator has gotten 45 comments while, here, it’s gotten four comments. The conversation at Y Combinator is quite lively. Check it out. ShareThis

• Dismantling the calculus pyramid

  Sol

  27 Oct 2009 | 8:30 pm

  Here’s a quick 3 minute TED video by Mathemagician Arthur Benjamin. The topic: Benjamin’s idea about how to change Math education. He makes the point that Math education is like a pyramid with all classes (e.g. algebra, geometry, trigonometry) building up to calculus. But, he argues, calculus is not very useful to many of us in our ordinary lives. So, what should the pinnacle of the Math pyramid be? Watch the video and leave your comments. ShareThis

• 
  Ars Mathematica

• Legendre, We Hardly Knew Ye

  Walt

  15 Nov 2009 | 3:46 pm

  It turns out that the standard picture of Adrien-Marie Legendre was actually a picture of his contemporary, the revolutionary Louis Legendre. (See the Notices article for the story. Gérard P. Michon has a photograph of the only known portrait of Adrien-Marie Legendre (a caricature). Next up: mathematicians discover that the inventor of algebraic topology was not, after all, the President of France during World War I.

• Spinning the Superweb

  Walt

  12 Nov 2009 | 8:03 am

  Oswaldo Zapata Marín is writing a series of essays about the history of superstring theory at Spinning the Superweb. His first essay, On Facts in Superstring Theory, describes something that is very mysterious to me as a math person: the process by which conjectures in string theory achieve a status akin to fact. Via Not Even Wrong.

• Some Set Theory Links

  Walt

  8 Nov 2009 | 1:28 pm

  If you’re interested in large cardinals, Akihiro Kanamori has made available a (typed rather than typeset) version of his and Magidor’s survey paper, The Evolution of Large Cardinal Axioms in Set Theory. If you’re interested in more advanced set theory links, this page provides links to individual author’s pages where you can find drafts of chapters for the upcoming three-volume Handbook of Set Theory.

• Bourbaki Archives

  Walt

  29 Oct 2009 | 3:19 am

  Via Peter Woit I see that there is a project to put the archives of Bourbaki online. These are the internal manuscripts that the group generated while writing their famous series of books.

• Class Weblog on Geometric Group Theory

  Walt

  15 Oct 2009 | 1:23 pm

  I just ran across an interesting weblog. Henry Wilton taught a course in the spring on geometric group theory, which is the use of topological techniques to prove theorems in group theory. He had his students write up the lecture notes for each lecture as a separate post on the class weblog, 392C Geometric Group Theory. I’m sorry that I didn’t find this site when the course was on-going. It would have been interesting to follow along with the class in real time.

• 
  Loren on the Art of MATLAB

• Coordinating Zero Removals from Multiple Arrays

  Loren

  19 Nov 2009 | 1:34 pm

  I've fielded some questions recently about how to coordinate multiple arrays changing simultaneously. One example is removing elements for two arrays in the case where either array holds a zero for the location. This is a good opportunity to reiterate the use of logical arrays and some useful associated functions (such as any and all). Contents Identify Pairs to Remove First Algorithm Second Algorithm Always Tradeoffs Identify Pairs to Remove Let's say I have 2 arraysa = [ 1 4 9 0 25 0 49 0] b = [ 1 0 3 0 0 6 7 8]a = 1 4 9 0 25 0 49 0 b = 1 0 3 0 0 6 7 8 and I would like to delete the…

• Empty Arrays with Flow of Control and Logical Operators

  Loren

  12 Nov 2009 | 11:54 am

  After reading last week's post on calculating with empty arrays, one of my colleagues mentioned some other behaviors with empty arrays that have tripped him up in the past. Today I will discuss how empty arrays work in the contexts of flow of control expressions (both conditional and looping, i.e., if and while) and short-circuit operators (i.e., && and | |). Contents Empty Arrays in Flow of Control Empty Arrays with Logical Operators Short-circuit Logical Operators (| | and &&) Examples References Empty Thoughts? Empty Arrays in Flow of Control Let me first start with plain…

• Calculus with Empty Arrays

  Loren

  4 Nov 2009 | 11:30 am

  MATLAB has had empty arrays since before I started using the program. When I started, the only size empty array was 0x0. When version 5 was released, empty arrays came along for the N-dimensional ride and got more shapely. Contents From the Newsgroup Dimensions Matter in MATLAB Empty Array Shapes Reference Got an Empty Question? Even relatively simple expressions involving empty arrays cause confusion from time to time, especially in concert with other rules in MATLAB (such as NaN values usually propagate from inputs to outputs). Let's play around a little with some empty arrays to get some…

• Dealing with Cells

  Loren

  21 Oct 2009 | 10:53 am

  A customer recently asked me this question at the MATLAB Virtual Conference. Contents Question about Summing Cell Rows Example Answer Cell Array Questions Question about Summing Cell Rows I was hoping you would cover cells some day. Here is a particular problem I was hoping to have a more elegant solutions for. A is a cell that has String (say names) in the first column, Numbers (say scores in tests 1 and 2) in the next two columns. Assume that each cell has only one value. Is there an easier way to calculate, say the sum of the two test scores than a for loop?Example Let's make some sample…

• Concatenating structs

  Loren

  15 Oct 2009 | 11:18 am

  From time to time, I get asked or see queries about how to concatenate two struct arrays to merge the fields. There's even a section in the documentation covering this topic. I thought I'd show it here to help people out. Contents Example Data mergeStruct Do You Need to Merge struct data? Example Data Suppose I've got some system for which I have collected information on a couple of individuals, including their names and ages. s1.name = 'fred'; s1.age = 42; s1(2).name = 'alice'; s1(2).age = 29;Later, I go back and collect the individual's heights (in cm).s2.height = 170; s2(2).height = 160;It…

• 
  Homeschool Math Blog

• Ratio word problem solved with block model and algebra

  15 Nov 2009 | 12:04 pm

  I guess it is time for some more problem solving, since someone sent this question in.Two numbers are in the ratio of 1:2. If 7 be added to both, their ratio changes to 3:5. What is the greater number?We can model the two original numbers with blocks. 1 block and 2 blocks makes the ratio to be 1:2.|-------||-------|-------|Now add the same thing to both (the 7): 7|-------|---||-------|-------|---| 7 The way I just happened to draw these suggests that I could just split the original block in two, and the problem is solved: 7|---|---|---||---|---|---|---|---| 7 Here, each little block is 7. The…

• Mixture problems - algebra 1

  10 Nov 2009 | 12:36 pm

  I am hoping you can help me. I can not remember how to solve mixture problems and how to set them up. Examples are as follows:A merchant made a mixture of 150lb. of tea worth $109.50 by mixing tea worth $1.25 a pound with tea worth $.65 a pound. How many pounds of each kind did he use?Organizing the information in a table or chart is usually very helpful in dealing with mixture problems. Other than that, it helps to study several examples and practice solving them yourself. After a while, it gets easier and patterns begin to emerge.The first problem has two unknowns. Let x be the amount of…

• Fact families on a whiteboard

  8 Nov 2009 | 9:53 am

  I just found this picture that I took of the fact families my 4-year old wrote on the whiteboard - totally on her own.There was a time she loved writing fact families like this every day. Being able to choose different color markers plus it being on the whiteboard seemed to be the main motivating factors, because she didn't want to write them on blank paper... Kids are funny.Then again, it allows us teachers to use colorful markers as a "motivational tool" : )Anyway, I was really happy that she had grasped the concept.

• Review of Math Apprentice

  2 Nov 2009 | 2:46 am

  Math Apprentice is a new free website, meant to show students how math is used in real world. In the game, you are like an apprentice at various companies, applying your math skills to challenges similar to those encountered in the real world and real companies.Main Street - Click to enlargeTo begin, you click the button on the home page of the site that says "Explore the Math". Then choose your character, and you'll be on the main street (see screenshot above) . Then use arrow keys to move right or left, and click to select a company to visit.The companies you can visit are:Sweet Treat Cafe…

• Percentages with mental math

  1 Nov 2009 | 9:38 am

  (This is an older post that I have revised plus added a video to it.)In this article I want to explore some ideas for using MENTAL math in calculating percents or percentages.I have made this video of percent & mental math strategies as well:And here are the ideas:Find 10% of some example numbers (by dividing by 10).Find 1% of some example numbers (by dividing by 100).Find 20%, 30%, 40% etc. of these numbers.FIRST find 10% of the number, then multiply by 2, 3, 4, etc.For example, find 20% of 18. Find 40% of $44. Find 80% of 120.I know you can teach the student to go 0.2 × 18, 0.4 × 0.44,…

• 
  About.com: Math

• Math: Write All About It

  20 Nov 2009 | 1:51 am

  A number of teachers have shared with me that they've had some success using math journals with their students. Personally, it's not a strategy I've tried when I was teaching. However, I do feel strongly about having students explain their mathematical thinking either verbally or in writing. To be able to explain solutions and strategies usually means there is deeper understanding of the concept. When a student isn't able to explain how they attacked a math problem, it may be that they're relying on a guess method with minimal strategies and it just happened to work.Some great questions for…

• Need Some Graph Paper?

  17 Nov 2009 | 10:36 am

  When you're in a pinch and don't really feel like stepping out to grab the graph paper you need, look no further! You'll find isometric paper of varying sizes, coordinate grids with and without numbers, various sizes of graph paper and dot paper. For whatever your need, I'm sure you'll find it here. The downside?You need blank paper and a printer!Need Some Graph Paper? originally appeared on About.com Mathematics on Tuesday, November 17th, 2009 at 18:36:54.Permalink | Comment | Email this

• Any Value in Memorizing Math Formulas?

  14 Nov 2009 | 4:46 am

  Some teachers require students to memorize the formulas and some don't. Some standardized testing allow formula sheets (referred to as cheat sheets by some) and some don't. It doesn't seem to matter who you ask, the answers always vary. I've gone both ways myself depending on the concept I'm addressing. For what's it's worth, I'm sitting on the fence with this one as I think there are certain formulas worth committing to memory and others that are always available at your fingertips. Check out what our users say about the value of memorizing (or not) formulas. Just to clarify: once upon a…

• Problem of the Week

  11 Nov 2009 | 2:35 pm

  To stimulate mathematical thinking, many teachers provide a problem of the week, some even do it daily. The problems are to stimulate extended thinking and problem solving. When you think about it, it makes great sense! Do you have a favorite? Why not share it. If not, here are a few to get you started: Pails of Water The Pig Pens Shorther Than you? The Horse Problem Not sure about problem solving? Here are some strategies to help you get started.Problem of the Week originally appeared on About.com Mathematics on Wednesday, November 11th, 2009 at 22:35:32.Permalink | Comment | Email this

• Multiplication Squares Worksheets: New This Week

  8 Nov 2009 | 12:09 pm

  Regardless of what curriculum your jurisdiction is working on, it's still important that students commit the multiplication facts to memory. Let me say that again, YES, it's still important that young learners commit the math facts to memory. Long ago, teachers had the time to help students commit the facts to memory. However, we are in the information age and when I look at the math curricula in various jurisditions, I don't see time for memorizing the basics. Therefore, this task will fall directly into the parents laps. It's been a long time since I've been in school, but my parents too…

• 
  Let's Play Math

• Math Teachers at Play #20

  Denise

  20 Nov 2009 | 4:55 am

  [Photo by shonk.] Welcome to the Math Teachers At Play blog carnival — which is not just for math teachers! If you like to learn new things and play around with ideas, you are sure to find something of interest. Let’s start the mathematical fun with a couple of puzzles in honor of our 20th edition: First, the shape to our right is an icosahedron, one of the Platonic solids. Each face is an equilateral triangle — can you count them? For more fun, make your own model. [Graphic from Wolfram MathWorld.] A rooted tree consists of a fixed node (the circled dot) with branches…

• Math Teachers at Play Changes

  Denise

  16 Nov 2009 | 6:56 am

  [Photo by nDevilTV.] This month, our Math Teachers at Play blog carnival switched to a once-a-month schedule. We’ll publish the third Friday of each month — which is this week! Teachers, homeschoolers, or anyone else who enjoys playing around with math: Wednesday night is the deadline to send in your thoughts, ideas, tips, or tricks about math using this handy submission form. Posts must be relevant to students or teachers of preK-12th grade mathematics. Old posts are welcome, as long as they haven’t been published in past editions of this carnival. Most bloggers have…

• Symmetry: Reality’s Riddle

  Denise

  13 Nov 2009 | 1:18 pm

  Hat tip to Dan at mathrecreation.

• Carnival of Mathematics #59

  Denise

  9 Nov 2009 | 4:42 pm

  Welcome to the Carnival of Mathematics! We’ve got a full roster this time, including roller coasters, topological Turán theory, a mathematician arrested as a spy, a plane running out of fuel mid-flight, speed limits in Conway’s Game of Life, and much, much more… The 59th Carnival of Mathematics features 59 blog posts (counting the multi-part posts and the carnival post itself) on a wide variety of interesting topics. Drop in and enjoy the browsing!

• Quotable

  Denise

  5 Nov 2009 | 5:15 pm

  “Let’s give the governor a break,” says Williams College mathematician Edward Burger. “If nothing else, he’s encouraging math education.” — Carl Bialik Coincidental Obscenity Deemed Extremely Dubious

• 
  QJ Math: Most Read Articles

• FLOWS OF G2-STRUCTURES, I

  Spiro Karigiannis

  30 Nov 2009 | 4:00 pm

  Spiro Karigiannis<br />Dec 1, 2009; 60:487-522<br />Articles

• BANACH-LIE ALGEBRAS WITH EXTREMAL ELEMENTS

  Antonio Fernandez Lopez

  13 Oct 2009 | 5:00 pm

  Antonio Fernandez Lopez<br />Oct 14, 2009; 0:321-32<br />

• FREIHEITSSATZE FOR ONE-RELATOR QUOTIENTS OF SURFACE GROUPS AND OF LIMIT GROUPS

  James Howie, Muhammad Sarwar Saeed

  31 Aug 2009 | 5:00 pm

  James Howie, Muhammad Sarwar Saeed<br />Sep 1, 2009; 60:313-325<br />Articles

• THE GAP BETWEEN LOCAL MULTIPLIER ALGEBRAS OF C*-ALGEBRAS

  Martin Argerami, Douglas Farenick, Pedro Massey

  31 Aug 2009 | 5:00 pm

  Martin Argerami, Douglas Farenick, Pedro Massey<br />Sep 1, 2009; 60:273-281<br />Articles

• A QUADRIC WITH ARITHMETIC PAUCITY

  V. Blomer, J. Brudern

  31 Aug 2009 | 5:00 pm

  V. Blomer, J. Brudern<br />Sep 1, 2009; 60:283-290<br />Articles

• 
  Logic Matters

• The blog is dead .... long live the blog!

  8 Nov 2009 | 2:12 am

  After almost 500 posts, this will be the last post here, meaning at this URL ........ but I'll be continuing the Logic Matters blog at logicmatters.net (and all the posts here at Blogger have been imported to that address, though the aesthetics are at the moment a bit primitive).Geeky explanation: At very long last, I'm joining the cool kids and am using the Wordpress platform on a hosted site. That's not in fact to make blogging easier -- I rather like the undistracting minimalism of Blogger -- but because Wordpress works as a nice content management system to build/maintain the rest of the…

• Gödel Without Tears -- 5

  6 Nov 2009 | 7:16 am

  Here now is the fifth episode on the idea of a primitive recursive function. The preamble explains why this matters and where this is going. [As always, I'll be very glad to hear about typos/thinkos.]The previous episodes are available:Episode 1, Incompleteness -- the very idea (version of Oct. 16)Episode 2. Incompleteness and undecidability (version of Oct. 26)Episode 3. Two weak arithmetics (version of Nov. 1)Episode 4. First-order Peano Arithmetic (version of Nov. 1)

• Ruse gets a beta minus.

  4 Nov 2009 | 3:00 pm

  Philosophers don't get asked often enough to write for the newspapers and weeklies: so it is really annoying when an opportunity is wasted on second-rate maunderings. Michael Ruse writes in today's Guardian on whether there is an "atheist schism". And he immediately kicks off on the wrong foot.As a professional philosopher my first question naturally is: "What or who is an atheist?" If you mean someone who absolutely and utterly does not believe there is any God or meaning then I doubt there are many in this group.Eh? Where on earth has that "or meaning" come from? In what coherent sense of…

• The Autonomy of Mathematical Knowledge -- Chap. 2, §§3-5

  4 Nov 2009 | 3:18 am

  To return for a moment the question we left hanging: what is the shape of Hilbert's "naturalism" according to Franks? Well, Franks in §2.3 thinks that Hilbert's position can be contrasted with a "Wittgensteinian" naturalism that forecloses global questions of the justification of a framework by rejecting them as meaningless. "According to Hilbert … mathematics is justified in application" (p. 44), and for him "the skeptic's path leads to the death of all science". Really? But, to repeat, if that is someone's basic stance, then you'd expect him to very much want to know which mathematics is…

• The Autonomy of Mathematical Knowledge -- Chap. 2, §§1 & 2

  2 Nov 2009 | 7:57 am

  Hilbert in the 1920s seems pretty confident that classical analysis is in good order. "Mathematicians have pursued to the uttermost the modes of inference that rest on the concept of sets of numbers, and not even the shadow of an inconsistency has appeared .... [D]espite the application of the boldest and most manifold combinations of the subtlest techiniques, a complete security of inference and a clear unanimity of results reigns in analysis." (p. 41 -- as before, references are to passages or quotations in Franks' book.) These don't sound like the words of a man who thinks that the…

• 
  The Unapologetic Mathematician

• The Implicit Function Theorem II

  John Armstrong

  20 Nov 2009 | 9:11 am

  Okay, today we’re going to prove the implicit function theorem. We’re going to think of our function as taking an -dimensional vector and a -dimensional vector and giving back an -dimensional vector . In essence, what we want to do is see how this output vector must change as we change , and then undo that by making a corresponding change in . And to do that, we need to know how changing the output changes , at least in a neighborhood of . That is, we’ve got to invert a function, and we’ll need to use the inverse function theorem. But we’re not going to apply it…

• The Implicit Function Theorem I

  John Armstrong

  19 Nov 2009 | 9:08 am

  Let’s consider the function . The collection of points so that defines a curve in the plane: the unit circle. Unfortunately, this relation is not a function. Neither is defined as a function of , nor is defined as a function of by this curve. However, if we consider a point on the curve (that is, with ), then near this point we usually do have a graph of as a function of (except for a few isolated points). That is, as we move near the value then we have to adjust to maintain the relation . There is some function defined “implicitly” in a neighborhood of satisfying the…

• The Inverse Function Theorem

  John Armstrong

  18 Nov 2009 | 8:09 am

  At last we come to the theorem that I promised. Let be continuously differentiable on an open region , and . If the Jacobian determinant at some point , then there is a uniquely determined function and two open sets and so that , and is injective on is defined on , , and for all is continuously differentiable on The Jacobian determinant is continuous as a function of , so there is some neighborhood of so that the Jacobian is nonzero within . Our second lemma tells us that there is a smaller neighborhood on which is injective. We pick some closed ball centered at , and use our first lemma to…

• Cramer’s Rule

  John Armstrong

  17 Nov 2009 | 8:56 am

  We’re trying to invert a function which is continuously differentiable on some region . That is we know that if is a point where , then there is a ball around where is one-to-one onto some neighborhood around . Then if is a point in , we’ve got a system of equations that we want to solve for all the . We know how to handle this if is defined by a linear transformation, represented by a matrix : In this case, the Jacobian transformation is just the function itself, and so the Jacobian determinant is nonzero if and only if the matrix is invertible. And so our solution depends on…

• Another Lemma on Nonzero Jacobians

  John Armstrong

  16 Nov 2009 | 4:07 pm

  Sorry for the late post. I didn’t get a chance to get it up this morning before my flight. Brace yourself. Just like last time we’ve got a messy technical lemma about what happens when the Jacobian determinant of a function is nonzero. This time we’ll assume that is not only continuous, but continuously differentiable on a region . We also assume that the Jacobian at some point . Then I say that there is some neighborhood of so that is injective on . First, we take points in and make a function of them That is, we take the th partial derivative of the th component function…

• 
  Basic-Mathematics

• Lemon Juice

  19 Nov 2009 | 3:25 am

  Delwyn sells lemon juice for 20c. Delwyn got 50 customers. How much did she earn? 20c into 1.00 = 5 5 into 50 = 10 answer

• Fun online math games

  16 Nov 2009 | 12:22 pm

  Looking for fun online math games? Look no more. Find here some of the best math games available online

• Mathman

  16 Nov 2009 | 10:42 am

  Do you know how to play pacman? Then, you will enjoy playing mathman. A fun way to sharpen and practice your basic mathematics skills.

• Area of an equilateral triangle

  15 Nov 2009 | 2:43 am

  Learn how to derive a formula that you can use to find the area of an equilateral triangle

• Addition games for kids

  15 Nov 2009 | 1:55 am

  Looking for good addition games for kids? Find here two of my favorite adding games ever

• 
  The Math Mojo Chronicles

• Speed Addition Demonstration and Tips

  Brian

  15 Nov 2009 | 3:13 pm

  I’m almost finished putting up the first week of the new “Quick and Dirty Multiplication” Math Mojo course. In the meantime, a few people have asked me to get to work on a “Quick and Dirty Addition” Math Mojo course. I won’t be able to get to that for a few weeks, but if you need immediate help, I’ve put together a few resources that I’ve created over the last year or so. The goal would be to take anyone who can already say, 3+ 6, and knows the difference between the ones column and the tens column, and be able to add huge columns and rows of…

• Mathematics in the Soviet Union

  Brian

  8 Nov 2009 | 7:47 pm

  There was a wonderful article in the Wall Street Journal today about mathematics in the former Soviet Union. It is worth reading for anyone interested in finding out a little about the inner beauty of math. Here’s a short except: what mathematics really is: “It was a wonderful education… Gelfand amazed me by talking of mathematics as though it were poetry.” In the mathematical counterculture, math “was almost a hobby,” recalls Sergei Gelfand. “So you could spend your time doing things that would not be useful to anyone for the nearest decade.”…

• Goodbye, Soupy

  Brian

  23 Oct 2009 | 4:39 am

  This will not have much to do with math, but a lot to do with mojo. One of my heros, Soupy Sales, died yesterday. Click here to view the embedded video. Soupy was a comedian, who hosted a children’s show in the 50’s and 60’s. He was a master absurdist, with an incredible sense of humor, and a wonderful respect for the minds of his audience. His show was booked as a “children’s show”, but his material was aimed a little higher – over the kid’s shoulders with a nodding wink to their parents. Soupy is among the other master creators, like Lewis…

• Martin Gardner – Happy Birthday!

  Brian

  21 Oct 2009 | 3:43 pm

  How could I have missed it? Or almost have missed it. Today is Martin Gardner’s 95th birthday. Who is Martin Gardner, you ask? I’m glad you asked that question! You can read more about it in today’s New York Times Science Section. I’ll write more about him soon, but for now, do yourself a huge favor and check out that article, then run to a library and check out any math books of his that you can find. Here’s another good article about Martin Gardner in the New York Times.

• What if we are Not Allowed to do it that Way?

  Brian

  15 Oct 2009 | 4:26 pm

  Here’s a dilemma for a lot of parents and other people who are trying to teach their kids math: The methods that many people use are far superior to the standard algorithms taught in elementary school, yet many benighted administrators and school policy-makers do not recognize this, and insist that students do things “the regular way.” Of course they don’t realize that other cultures (besides the U.S.) have a different “regular way” that sometimes beat the poop out of our way – which is proven by our low ranking among most other countries of the world…

• 
  The Everything Seminar

• Protons have orbited the LHC!

  Jim Pivarski

  20 Nov 2009 | 12:19 pm

  The beam went three times around the LHC ring: see CMS’s e-commentary and CERN’s twitter.  This is the milestone that was a big media event last year (September 10, 2008). Update: now it’s 500 times around the ring (about 0.05 seconds).  Last year’s record was about 9 minutes of continuous beam. Update: up to 9 seconds, 30 seconds (50k events seen by CMS)… Update: and now a beam in the other direction has made a full orbit.  (All you gotta do is smack ‘em together!)

• “Beam-splashes” to arrive at CMS soon, possibly this weekend

  Jim Pivarski

  7 Nov 2009 | 10:20 am

  See CMS e-commentary for live updates. “Beam-splashes” are when a beam is threaded part-way through the LHC ring, then deliberately collided with an absorbing block of tungsten to stop it, upstream of a detector. Many particles are created in this collision, most of them are absorbed, with the exception of the muons and neutrinos. CMS can detect muons, and what it sees is a huge splash of activity, shown in this event display from September, 2008. The blue bars indicate huge deposits of energy in the calorimeters. They seem to project from the center of the detector, but this is…

• The Beam is Back

  Jim Pivarski

  28 Oct 2009 | 10:20 am

  A little over a year after the highly publicized start-up and break-down of the LHC, the damage has been repaired, new protection systems are in place, and all sectors are cold and ready for beam. Yesterday, the first injection test of 2009 was completed— beams of protons and heavy ions were successfully threaded into the LHC beampipe from its predecessor, the Super Proton Synchrotron (SPS). The beams were allowed to flow as far as the first experiments in both directions, ALICE on the clockwise side, LHCb on the other. The publicity of the turn-on events will be somewhat more subdued…

• What killed Madame Curie? (Part 4)

  Jim Pivarski

  7 Sep 2009 | 7:26 am

  New York City, 1956 Leaning on a Chinese restaurant at a busy street corner in Greenwich Village, I crossed my legs, tipped my hat low, and quietly panicked. This case is turning into a nightmare: dozens of suspects, growing daily, and they all seem to swap places when you’re not looking. A pion couldda done it; pions seem to be some kind of front for the nuclear force that Madame Curie was playing with before she died. But leave a pion to itself and it disintegrates into a muon and a neutrino, neither of which claims to have ever heard of nuclear forces. Radiation in the form of muons…

• What killed Madame Curie? (Part 3)

  Jim Pivarski

  27 Jun 2009 | 4:48 pm

  Ithaca, NY, 1948 After a wrong turn in Albuquerque, I caught up with Bugs Bunny, alias Richard Feynman, somewhere near the ends of the earth.  Up to my elbows in snow-drifts, I spied on the little window to his office, in which he seemed to be doing normal professor-things, plus wild gesticulations.  I decided on a particularly frozen morning that I would have to risk visibility if I was to get answers, so I enrolled at Cornell, posing as a G.I. bill student.  In Professor Feynman’s introductory physics lectures, I could see that there was something remarkable happening here. …

• 
  bodmas blog

• Platforms

  Keith Burnett

  20 Nov 2009 | 11:59 am

  “An organization that wins by exercising power starts to lose the ability to win by doing better work. And it’s not fun for a smart person to work in a place where the best ideas aren’t the ones that win.” Paul Graham, via daring fireball I’m getting serious about mobile platforms. I need to decide if I’m buying an iPhone or an Android. A lot of younger colleagues and friends love their iPhones (go for it Jonathan), but I’m leaning towards an Android at present for the openness. We can ignore all the app store hassle by using web apps that run in the…

• Fish Soup

  Keith Burnett

  13 Nov 2009 | 12:11 pm

  “It is easy to turn the aquarium into fish soup, but it is more difficult to reverse the process”–Lech Walesa

• Possibility space worksheet

  Keith Burnett

  8 Nov 2009 | 11:39 am

  Scroll down for scientific poster stuff Download a one side worksheet on possibility spaces in probability [ PDF ]. The worksheet has an example of throwing two dice and adding the scores, and tries to explain why there ate 36 equally likely outcomes, of which six happen to give a score of 7. The first version of this worksheet had some of the possibility space illustrated above filled in as a guide. That proved counter productive as students forgot to count the filled in squares as outcomes! Table formatting in OpenOffice.org follows a slightly different approach to the same process in MS…

• Rodent on steroids

  Keith Burnett

  7 Nov 2009 | 1:49 am

  Orvieto, Italy, November 6, 2009: In partnership with the OpenOffice.org community, WarMouse announced the release of the OpenOfficeMouse, the first multi-button application mouse designed for the world’s leading open-source office productivity suite. With a revolutionary and patented design featuring 18 buttons, an analog joystick, and support for as many as 52 key commands, the OpenOfficeMouse is intended to provide a faster and more efficient user interface for OpenOffice.org applications such as Writer and Calc than the conventional icons, pull-down menus, and hotkeys presently…

• Scientific Poster Links

  Keith Burnett

  5 Nov 2009 | 4:49 am

  Students on science degrees usually learn how to present findings in the form of a ‘poster’. A science poster is a special kind of wall display invented so everyone who attends a conference can present their results even though there is not enough time for them all to speak. MS PowerPoint (and OpenOffice Impress) can be used to make posters easily – just use a single slide resized to A1 or A0 depending on the size of your poster. Then set up columns using text boxes and import (or draw) some images. Must Below are some links to places where you can find out more about…

• 
  ChapterZero

• Graph layout by Stress Majorization by Optimization of A Complicated Function

  Alex

  6 Nov 2009 | 6:30 pm

  I haven’t had much to talk about lately– the Probabilistic Graphical Models course is eating up my time like crazy: I haven’t had time to do anything but that and prepare my lectures and homeworks for the Matlab/Mathematica course– but I have been doing a lot of coding for the course I’m teaching and the course I’m taking. Most of it isn’t fit for public consumption, but some of it is worth sharing/archiving here. The code below takes the weighted adjacency matrix of a graph and returns a planar embedding using stress majorization by optimization of a…

• OS Choices

  Alex

  25 Oct 2009 | 3:10 pm

  Ubuntu 9.10, or Windows 7? I like the idea of Ubuntu, and I can do almost everything I want with it, with the important exception of easily accessing the campus wireless network. I also don’t know if it interfaces with projectors as easily as Windows does. Those are my two main issues. Other than that, there’s the eye candy factor: Windows probably will have a slicker interface. The change from Hardy to Jaunty was striking to me, visually, but what I’ve read of Karmic Koala doesn’t indicate that I can expect a similar jump. I could always do a dual boot again, but…

• Good news for people who like bad news

  Alex

  20 Oct 2009 | 6:56 pm

  I’ve discovered, once again, the problem with using random test cases. I thought I’d come up with some nice manipulations that reduced the nonnegative least squares problem to a problem on a polytope (more relevantly, a bounded convex set), so I could apply any number of methods that have been developed for constrained minimization over bounded convex sets. When I tested one such algorithm in combination with my reduction, it gave wonderful results. But now, I’ve realized that my reduction was completely wrong (at some point I implicitly assumed that the matrix I’m…

• example MATLAB animation -> animated gif

  Alex

  15 Oct 2009 | 7:23 pm

  I always forget how to make animations in MATLAB, and I never knew how to make animated gifs before. I figured this out for the MATLAB course, but I don’t think I’ll go over it in class, since I don’t want to get into handle graphics nastiness. But for my own reference, and anyone who may be looking for ways to do this, this code gives the gist of it: clf theta = linspace(0, 2*pi, 200); x = cos(theta); y = sin(theta); hbead = line(x(1), y(1), 'marker', 'o', 'markersize', 8); htrail = line(x(1), y(1), 'marker', '.', 'color', 'r'); axis([-1 1 -1 1]); axis('square'); im = {};…

• Any mathematicians want to give Sex Advice?

  Alex

  30 Sep 2009 | 11:14 pm

  I know several mathematicians read this blog. Hahahahahaha. Seriously, if you are an element in this set and are interested in participating in the Nerve.com “Sex Advice From” column, let me know. They’re looking for mathematicians to go through an interview, by email or over the phone. (Apparently graduate students count, or they wouldn’t have contacted me?) They’ll publish some of your answers along with a picture. Here are three sets of past interviews from the column, so you’ll know what you’re signing up for:…

• 
  Computational Complexity

• Citing Papers

  Lance

  20 Nov 2009 | 4:57 am

  A student asked me which version of a research paper to cite, a journal (the last reviewed version) or a conference (the first reviewed version) of a paper. I generally cite papers in this precedence list.The fully refereed journal version, even if it is "to appear".The reviewed, though not usually refereed, conference proceedings version, again even if it is "to appear".On an electronic archive, like arXiv or ECCC.As a departmental technical report.On a generic web page, like a personal page.As a "Manuscript", if I have seen the paper but it's not publicly available.As "Personal…

• Laptops in Church?

  GASARCH

  19 Nov 2009 | 8:51 am

  There are now bibles online where you can click for different versions, different translations, different interepretations, historical context, etc. The same is true, or will be soon, for other faith's holy books as well. Will there come a day when people bring their laptops (or smaller devices) to church? They can claim that they are looking up things in their online bible. Some will indeed be looking up bible passages. Some will be balancing their checkbook. Some will be reading blogs. Some will be looking at porn. Will the church need to deal with this? If it does not distract others (and…

• FOCS Videos

  Lance

  18 Nov 2009 | 3:38 am

  As I tweeted yesterday, the videos of talks from the 2009 FOCS conference are now online. Thanks to FOCS PC chair Daniel Spielman and Georgia Tech's ARC Center for making it happen. Let me be a bit Billish (or is it Gasarchian) and make my comments as questions.  Which talks are most worth watching? How many of these videos do you plan on watching? Do you get value over these talks over reading the papers? The papers aren't on the IEEE DLs yet but Shiva has collected some links. If STOC/FOCS talks were generally available on-line shortly after the conference, would this…

• A Prayer Book for the Internet Generation

  Lance

  17 Nov 2009 | 5:10 am

  As a young kid in the Reform Jewish community we used the Union Prayer Book, a traditional book with Hebrew on the right and English on the left with lots of instructions for page jumping, standing, when to sing and whether everyone should speak. When I became a Bar Mitzvah in 1976, the temple sisterhood gave me a copy of the new prayer book, Gates of Prayer. The Gates of Prayer had services in a linear fashion using different fonts to denote when to sing and who should speak and with instructions on when to stand and sit. One could run an entire service giving no instructions from the Bima.

• Rules about Blogs becaues Blogs RULE!

  GASARCH

  16 Nov 2009 | 8:38 am

  There are now laws about blogging and twittering that Lance and I (and all the bloggers) will need to be aware of. Here is a short summary: If a blogger posts about a product that she got for free then she must disclose that she got it for free. (Applies to guys also.) There are no such laws for traditional media. Some questions: What problem is this trying to solve? Did Lance get a free copy of some textbook, twitter about it, and it sold 1,000,000 copies? Or did Alaska Nebraska twitter about (say) a car she got for free and it sold alot? And if she did, so what? If the book or car is…

• 
  Natural Blogarithms

• How do you measure two-thirds?

  SplineGuy

  18 Nov 2009 | 6:53 am

  From an article by Mary Ann Bragg which appeared on CapeCodeOnline and was also printed in this month’s College Mathematics Journal: TRURO — Voters narrowly approved one of four zoning amendments late Tuesday night at the annual town meeting. But town officials were still looking at the exact vote count on that article yesterday. In a vote of 136 to 70, voters passed a new time limit on how quickly a cottage colony, cabin colony, motel or hotel can be converted to condominiums. The new limit requires that those properties be in operation for three years before being converted to…

• Interesting facts about Euler

  SplineGuy

  17 Nov 2009 | 8:30 am

  I’ve not studied much of the history of mathematics but occasionally I read from a few books I have on my shelf on the subject.  When my mind is bogged down and I am unmotivated on my current projects, I pick up, say, Makers of Mathematics, by Stuart Hollingdale. Today, I flipped open to the chapter on Leonhard Euler (one of my mathematical heroes) and learned (or re-learned) a few interesting facts about the man. Entered the University to study theology and Hebrew but his mathematical abilities attracted the attention of Johann Bernoulli who gave him a private lesson once a…

• How the Psalms Motivate Us to Marvel at Creation

  SplineGuy

  30 Oct 2009 | 6:45 am

  This week I was given the privilege of leading our campus Environmental Stewardship Bible Study.  Currently the study is walking through various sections of the Bible in order to provide a scriptural foundation for concepts in environmental stewardship.  It was my good pleasure to lead a study on Psalms.  While the actual Bible Study was driven by some excellent discussion, much of the material in the study below I was unable to get to.  This outline has been posted in our Blackboard classroom for the Bible study but I also post it here for those folks that have been…

• Where the Study of Environmental Stewardship Begins

  SplineGuy

  20 Oct 2009 | 10:17 pm

  In several lengthy discussions that I’ve had with friends and colleagues over my new interest in environmental stewardship, inevitably we begin discussing the stereotypes of environmental activists.  Being raised in West Texas my whole life, I haven’t really encountered very many individuals that would be classified as environmental activists, but I’ve certainly heard my fair share of disparaging political epithets: hippy, environmentalist wacko, tree hugger, ecoterrorist, econazi, etc. If you have a personal conviction to care for God’s creation and feel that abuse to the…

• Euler’s Method in Excel – Very Simple

  SplineGuy

  19 Oct 2009 | 2:56 pm

  During Calculus last week, we covered slope fields and Euler’s method of first order initial-value problems of the form During class we demonstrated the use of slope field to perform a basic qualitative analysis. We utilized a couple of different online applets as well as Maple 13. Visualizing Slope Fields and solutions Another similar page, with zoom Direction Fields – A Maple 13 Worksheet Below is a short demonstration of how we set up a simple application of Euler’s Method in Excel 2007. Consider the simple initial value problem: Recall that Euler’s Method is given by…

• 
  Precal Blog

• Fall Play Teaser and Substitute

  EmilyM

  20 Nov 2009 | 12:56 pm

  Hey everyone, its Emily. I’m blogging for George since he wasn’t here yesterday due to his involvement in the fall play. Thankfully, we didn’t do too much during class.  The majority of the hour was spent watching the teaser for the fall play. For the rest of class, we had a substitute because Mr. B was gone. During this time we started working on our claim problems for section 3.3 in the book. This section deals largely with the new graphs (Csc, sec, tan) we’ve been learning about in class. No word yet on when the claims are due, but you can probably bet on having…

• More Csc and Sec Sinusoids

  Alex

  18 Nov 2009 | 9:20 pm

  So today in class we were given a worksheet to do.  The first three problems on the worksheet dealt with csc and sec graphing and the last problem dealt with tan which we will be learning tommorow.  One of the three problems we were supposed to do in class today was graph y=3+csc6( theta-30). To do this we first need to find the asymptotes and the high and low points of the sine graph since it is csc.  We know the vertical midline of the sine graph is 3 since it is 3+csc6( theta-30). Then the amplitude is one and since the midline is three the graph’s vertical high point…

• My mistake

  Patrick

  18 Nov 2009 | 1:39 pm

  I forgot to include a graph of tan! Lo siento. Anyways heres what a graph of tan looks like (with and without the cos/sin graph)

• November 18, 2009 Tan graphs YEA!!!!!

  Patrick

  18 Nov 2009 | 1:36 pm

  Alrighty so we started class with a Worksheet that was basically practice of drawing csc and cos graphs (preferably without the “training wheels” of a sin or cos graph.) The we were confronted with the problem of how to graph a tan function. We then discussed how a tan graph is made from using both cos and sin graphs. Using the following logic. So if you were to find what sin(0) (I can’t get pheta so pretend thats what zero is) equals it would be Sin (0) V/R your could then solve for V and get V= Sin(0)*R. Then if you would do the same for cos(0) it would be Cos(0) = U/R.

• Tangent – Live!

  Reversearp

  18 Nov 2009 | 7:58 am

• 
  The Calculist

• Ezra: Function calls are not stack frames

  4 Nov 2009 | 1:30 pm

  I don't have much to add to this but Ezra's saying things that are true:Tim Bray is spreading more misinformation about tail recursion. He describes it this way: It looks like a subroutine call, but in the case where it occurs as the last thing in the routine, it magically, silently, and automatically gets turned into, now how did I put it? “A highly controlled and structured GOTO.” A tail-call is a subroutine call. The efficient implementation does not magically transformed into something else; if it doesn't create a stack frame on such a call, it's because one simply isn't relevant.It's…

• Proposed json.plt change

  8 Sep 2009 | 7:49 am

  I'm not sure how many users I have of my json.plt PLaneT package, nor how many of them read my blog. But I thought I'd see if I could take a straw poll here. I'm thinking about changing the data definition in a backwards-incompatible way. What if I said:A jsexpr is one of:'nullbooleanstringintegerinexact-real(vectorof jsexpr)(listof (cons symbol jsexpr))The nice thing about this representation is that it's easier to quote and quasiquote. The down-sides are that array manipulation is a little less convenient, and table lookup is slower.Another alternative is:A jsexpr is one of:#:null boolean…

• Mitchfest blog

  3 Sep 2009 | 2:07 pm

  We've created a Mitchfest blog where we'll be posting updates on new material as it becomes available, including presentation slides, videos, and publication of issues of the Festschrift.

• Quote of the day

  17 Aug 2009 | 9:52 am

  "What's surprising to me is that this language ever managed to achieve widespread use - but I guess it's just another example of how you can break a whole bunch of precious rules and the sky doesn't necessarily fall in. Software is full of people declaiming their 'thou shalt not' lists, and right across the street there's another bunch of people breaking those very rules quite profitably." -- Daniel Earwicker

• Mitchfest program

  11 Aug 2009 | 1:28 pm

  We've posted the Mitchfest schedule and program!

• 
  The Math Less Traveled

• Number bracelets

  Brent

  17 Nov 2009 | 3:20 pm

  Recently I’ve been volunteering with the middle school math club at Penn Alexander, a PreK-8 school in my neighborhood. Today we did (among other things) a fun activity I’d never seen before, called “number bracelets”. The students seemed to enjoy it; it worked especially well with a bunch of students all working on it at the same time since they were able to compare notes. Here’s the idea: start with any two one-digit numbers you like. For example, let’s choose 4 and 6. Next, add the two numbers: 4 + 6 = 10. Throw away the tens digit of your answer (if…

• minim

  Brent

  4 Nov 2009 | 9:00 am

  A fun game I discovered recently, minim. In each level you start out with a network of numbered nodes, and the object is to successively combine the nodes according to certain mathematical rules in order to end up with only a single node. The levels start out easy but get fiendishly difficult by the end. My only complaint is that it isn’t possible to make up your own custom levels.

• Logicomix: An Epic Search for Truth

  Brent

  2 Nov 2009 | 4:58 am

  I recently acquired a copy of Logicomix: An Epic Search for Truth, by Apostolos Doxiadis and Christos Papadimitriou, with art by Alecos Papadatos and Annie Di Donna. It defies categorization: is it a comic book? A biography? A book of philosophy? Of history? Of mathematics? Well, it’s all of these things, and manages to pull it off with grace and style. Logicomix is a graphic novel focusing on the story of Bertrand Russell, the English mathematician and philosopher, and the quest at the beginning of the twentieth century to discover a logically rigorous foundation for mathematics. This…

• The hyperbinary sequence and the Calkin-Wilf tree

  Brent

  18 Oct 2009 | 11:45 am

  Recounting the RationalsRecounting the Rationals, part IRecounting the Rationals, part II (fractions grow on trees!)Recounting the Rationals, part IIIRecounting the Rationals, part IVRecounting the Rationals, part IVb: the Euclidean AlgorithmChallenge #12: sums of powers of twoChallenge #12 solution, part IIMore hyperbinary funHyperbinary conjecture seeking proof for a good time, long walks on the beachThe hyperbinary sequence and the Calkin-Wilf tree And now, the amazing conclusion to this series of posts on Neil Calkin and Herbert Wilf’s paper, Recounting the Rationals, and the…

• Hyperbinary conjecture seeking proof for a good time, long walks on the beach

  Brent

  12 Oct 2009 | 6:31 am

  Recounting the RationalsRecounting the Rationals, part IRecounting the Rationals, part II (fractions grow on trees!)Recounting the Rationals, part IIIRecounting the Rationals, part IVRecounting the Rationals, part IVb: the Euclidean AlgorithmChallenge #12: sums of powers of twoChallenge #12 solution, part IIMore hyperbinary funHyperbinary conjecture seeking proof for a good time, long walks on the beachThe hyperbinary sequence and the Calkin-Wilf tree Here’s the latest progress on the hyperbinary sequence. We’re trying to figure out the inverse relation of the function : given a…

• 
  Rational Mathematics Education

• Elitism and mathematics education: Why tracking is still wrong

  17 Nov 2009 | 5:38 pm

  As I survey the many pressing issues facing US education in general and mathematics education in particular, one that never goes away is tracking (or "streaming" or whatever euphemism is being served up by its advocates these days). To me, it is anathema. Not that I see no reasons to mix things up within classrooms frequently so that there are occasionally homogeneous as well as heterogeneous groupings along various constructs, including ability, gender, ethnicity, and others). But I will never tolerate or support segregating kids all or most of the time along such lines. And therein lies an…

• Good Tests, Bad Tests: Can The Testing Fanatics Tell The Difference?

  29 Oct 2009 | 1:09 pm

  And do they really care?Consider the following problem:=====================================3, 4, 6, 7, 10, 12The number n is to be added to the list above. If n is an integer, which of the following could be the median of the new list of seven numbers?I. 6II. 6 1/2III. 7(A) I only (B) II only (C) III only (D) I and III only (E) I, II, and III==============================================In considering your evaluation of the question, you may wish to know the following facts: this is the 13th of 16 questions for which the total time allotted is 20 minutes. The question appeared on the last of…

• You Want Proof? I'll GIVE You Proof!

  13 Jun 2009 | 10:17 am

  Once again, the fires of discord are raging on math-teach@mathforum.org. One of the threads I've been embroiled in revolves on several axes: one is about teaching pure mathematics in K-12. Another is about visual proofs. The one I wish to specifically deal with here is the one that links the two: what comprises the nature of proof in elementary school mathematics classrooms and how do we get students in those grades to develop their notions of what a mathematical proof actually is?The problems in having this sort of conversation in a hostile forum like math-teach are legion. One problem is…

• Math Test - a poem.

  3 Jun 2009 | 2:07 pm

  I occasionally get requests to post guest pieces at RME, but invariably they prove to be from people looking to promote some sort of commercial web site or service. As those so requesting fail to offer to adequately grease my palm, I always refuse, sometimes in less than friendly fashion.However, I received a work today of such outstanding literary merit, so fraught with relevance to many of the concerns of this blog, that I could not refuse despite the lack of financial incentives from the author. For now, I am going to publish this without attribution to the author, though in due course his…

• Professor Frank Quinn Says: "Calculators? Whoa!"

  25 May 2009 | 10:15 am

  Frank Quinn doesn't like calculators:(what about his dog?)The current (May 2008) NOTICES OF THE AMS contains the following opinion piece from Virginia Tech mathematician, Frank Quinn. It bears noting that the mathematics education folks at his university are members of the math department, which must make for some fun faculty meetings.K–12 Calculator WoesIn the third grade my daughter complained that she wasn’tlearning to read. She switched schools, was classified asLearning Disabled, and with special instruction quicklycaught up. The problem was that her first teacher useda visual word…

• 
  The Math Factor Podcast

• Harris: Myers Game

  Gelada

  20 Nov 2009 | 6:18 am

  Here’s an idea for a general tiling game. Start with a set of shapes and 2 (or more) people. Each person takes it in turn to place onto a patch of tiling. The winner is the last person to move. So here’s the puzzle: Take the Myer’s polyhex tile: Can you: Find rules to avoid easy draws (for example wandering off in one direction to infinity). Find a winning strategy? I personally have no idea, so this is a challenge problem! If you have access to a Laser Cutter or other fancy computer device the cut files are on Thingiverse.

• GL. Math 2033

  strauss

  19 Nov 2009 | 3:13 pm

  So, I’m teaching a new course, Math 2033, Mathematical Thought, and it’s going great! I’d like to take a moment to write about it! (This is one reason the MF has been kinda slow lately; another is that I’m chair) When it’s fully up and running, we’ll have about 150 students in one large section each semester (we’re starting with about 100). In a nutshell, it’s the Math Factor, as a course. So, the list of topics is pretty familiar; from the podcast you are pretty well acquainted with the kinds of things I like to share: game theory, encryption, a little number…

• Morris: Follow Up: Living With Crazy Buttocks

  Stephen Morris

  14 Nov 2009 | 12:31 pm

  In Living With Crazy Buttocks  I posed a problem where 20 party guests were each given an unusual book.  These books were placed in identical boxes.  The guests enter the room with the boxes one at a time and are allowed to open half of the boxes.  They leave by a different door and cannot communicate with the other guests.  The room is put back identically before the next guest enters. If every guest finds their book then the whole group win a trip to Paris. What is their best strategy? This puzzle comes from a Peter Winkler book, Mathematical…

• GK. Mythematics

  strauss

  12 Nov 2009 | 4:49 pm

  Michael Huber discusses the mathematics of the Twelve Labors of Hercules!  

• Yoak: Batteries, and the Problem of the Week

  jyoak

  11 Nov 2009 | 11:17 am

  Recently I discovered Stan Wagon’s Problem of the Week.  This is a delightful mailing list / site and some of the problems are in the vein of puzzles I post here.  Recent problem 1125 captured the attention of several Math Factor authors so I thought I’d post the puzzle here as an excuse to introduce you all to that list. You have eight batteries and know that four are good and four are dead, but don’t know which are which.  Your only method of testing them is to insert two into a device that will work if you’ve put in two good batteries and not…

• 
  WordPress Tag: Mathematics

• คณิตศาสตร์เต็มหน่วย

  SoClaimon

  21 Nov 2009 | 3:11 am

  204211     คณิตศาสตร์เต็มหน่วย     Discrete Mathematics (Sets, sequences, and functions; logic; the growth of functions; methods of proof and mathematical induction; recursive definitions and algorithms; counting methods and recurrence relations; relations; introduction to graph theory.) (204211 มหาวิทยาลัยเกษตรศาสตร์)

• links for 2009-11-20

  Colleen Young

  20 Nov 2009 | 8:05 pm

  Cybraryman Internet Catalogue  web20 (tags: web2.0) Sharepoint or Moodle? – Classroom 2.0 (tag

• ทุนอีราสมุสมุนดุส ป.โท ด้านดาราศาสตร์

  ToeflThailand

  20 Nov 2009 | 7:21 pm

  ทุนอีราสมุสมุนดุส ป.โท ด้านดาราศาสตร์ วันที่ 24 พฤศจิกายน 2552 เรียบเรียงโดย: ดร.สิระ สุทธิคำ, มณเฑี

• The most essential thing Mathematics have taught me for real life

  dasuxullebt

  20 Nov 2009 | 7:03 pm

  When discussing with non-mathematicians about why I want to become a mathematician, what a mathematician’s work at a university is, and what it is good for, I often answer with the counterquestion what art is good for, because usually, there are two kinds of people asking such questions: the ones that like at least some kind of art, be it just folk music or modern films, and the pragmatic people which believe that investing ressources into research that has no immediate practical application means wasting them, of which most are die-hard capitalists or die-hard communists, which is a…

• Calendario matemático 2010

  Carlos

  20 Nov 2009 | 4:03 pm

  Hola a todos, Comparto con todos ustedes el calendario matemático que acabo de descargar. (sólo se muestra los meses de enero a mayo) Ejemplo. View this document on Scribd Los diferentes usos que se le puede dar a este calendario van desde la decoración de un aula al trabajo matemático para las fechas que se seleccione convenientemente. Es imprecindible revisar previamente el contenido del calendario, ya que está dirigido a un público con conocimientos matemáticos básicos. Puedo mencionar que sería mejor aplicarlo en la clase con jóvenes de 14 años en adelante. Finalmente, invito a…

• 
  Mr. L's Math

• Algebra Activities that Reach the Kids and Teach the Standards

  Bill Lombard

  5 Nov 2009 | 11:34 am

  I will be presenting a session at the California Math Council’s conference in southern California on 7 November, 2009 with the title of this blog article. I’ve included a link below to the conference presentation. This session will cover several pedagogical topics that have made my students successful learners, including Conceptual Layering, as well as snippets of three popular Teacher to Teacher Press activities that illustrate these topics. I’ll also be presenting another session about GeoGebra, the free open-source software program that is gaining wide acceptance across…

• George Polya, Master Problem Solver – a Model for All Math Teachers

  Bill Lombard

  27 Oct 2009 | 1:20 am

  George Polya George Polya was a master of problem solving, and his effect on other teachers has been extraordinary. His most popular book, How to Solve It, has sold over a million copies. As is the case with many great books, Polya had been turned down by three publishers before finding one to publish the English version in the United States. It has also been translated into 17 languages. I remember reading this book as a high school student and thinking “What a great writer Mr. Polya is, how clearly he presents his topic: Problem Solving.” His approach has had a lasting…

• Martin Gardner – For Decades, Puzzling People With Mathematics

  Bill Lombard

  25 Oct 2009 | 10:54 am

  Martin-Gardner Martin Gardner has published over 70 books and is the chief person responsible for the widespread interest in recreational mathematics. He turned 95 on 21 October, 2009 and celebrated by publishing another book. He authored the Mathematical Games column in Scientific American for 25 years. He quite possibly has introduced more people to the fun inherent in mathematics than any other person. I currently have twelve of his books, and occasionally reread one and get enthused about his topics anew. The New York Times ran a special article on this special person recently. For more…

• First North American GeoGebra Conference – Ithaca, New York

  Bill Lombard

  4 Oct 2009 | 8:08 pm

  The First North American GeoGebra Conference will be held 27-28 July, 2010 at Ithaca College in Ithaca, New York. I’ve been honored to be a part of the Scientific Committee for this conference. This committee has the responsibility of reviewing conference proposals. I’m looking forward to an interesting experience seeing how others use the powerful program, and also what’s in the future for this creative software. The website above has just been created and will be updated as information becomes available. Mark you calendar for an exciting two days with fellow GeoGebra…

• 20 Free Online Math Games for Students

  Bill Lombard

  26 Aug 2009 | 6:24 pm

  Karen Schweitzer The following is a Guest Post from education writer Karen Schweitzer. Karen is the About.com Guide to Business School. She also writes about online colleges for OnlineColleges.net. ++++++++++++++++++++++++++++++++++++++ Interactive math games can make it easier for students to grasp some of the more difficult or tedious concepts in math. The Internet is a good source of free interactive math games for students of all grade and skill levels. Here is a list of 20 math games and sites for K-12 students to explore: APlusMath – APlusMath offers a wide range of mathematics…

• 
  MathNotations

• The Return of the WarmUp Challenges!

  Dave Marain

  15 Nov 2009 | 6:53 am

  Just when you thought that MathNotations is on permanent hiatus or in hibernation, here are a couple of WarmUps/Problems of the Day/Test Prep/Challenges/// to consider for your students.  Actually, I'm embarking on a new venture - an online tutoring website with live audio and video for OneOnOne math tutoring for Grades 6-14 (through Calculus II). In addition, I'm also working on setting up a small group (5-10 students) online SAT or ACT Course grouped by ability (a 600-800 SAT group, a 450-600 group, etc.).  If you're interested in getting more information about these before the…

• THE OPEN-ENDED CONTEST PROBLEM AND SOLUTIONS

  Dave Marain

  4 Nov 2009 | 3:04 am

  As promised, here is the open-ended, rubric-based, holistically scored, performance-assessed, student-constructed first problem from MathNotation's Third Contest:1. A primitive Pythagorean triple is defined as an ordered triple of positive integers (a,b,c) in which a2 + b2 = c2 and the greatest common factor (divisor) of a, b and c is 1. If (a,b,c) form such a triple, explain why c cannot be an even integer.Comments(a) The content here is number theory. Is some of this covered in your district's middle school curriculum or beyond? More importantly, at what point do students begin to formulate…

• RESULTS OF THIRD MATHNOTATIONS CONTEST and OTHER NEWS...

  Dave Marain

  3 Nov 2009 | 6:00 am

  FINALLY -- THE RESULTS ARE IN!!I apologize for the delay in getting these results out. The participating schools have all been notified.NOTE: If any participating school did not receive an email from me, the advisor should email me. Also, if I misspelled anyone's name pls let me know and I'll correct it immediately!INITIAL COMMENTS ON CONTEST, ETC...MEAN SCORE: 5.6 PTS OUT OF 12TOPICS INCLUDED Number Theory, Geometric Sequences, Function Notation, Geometry, Discrete Math, Quadratic Functions, and Absolute Value Inequalities (advanced level)Twenty schools registered from around the world, but…

• A Rant, An Update and Model Problems for You

  Dave Marain

  12 Oct 2009 | 3:42 am

  And the seasons they go round and round And the painted ponies go up and down We're captive on the carousel of time We can't return we can only look behind From where we came And go round and round and round In the circle game...Oh, how I love Joni Mitchell's lyrics made famous by the inimitable Buffy Sainte-marie. Oh, how The Circle Game lyrics above describe my feelings about the state of U.S. math education. I feel I've been on this carousel forever. But I do believe that all is not hopeless. I do see promise out there despite all the forces resisting the changes needed to improve our…

• Another Sample Contest Problem - Counting...

  Dave Marain

  5 Oct 2009 | 3:29 am

  There is still time to register for the upcoming MathNotations Third Online Math Team Contest, which should be administered on one of the days from Mon October 12th through Fri October 16th in a 45-minute time period.Registration could not be easier this time around. Just email me at dmarain "at" "gamil dot com" and include your full name, title, name and full address of your school (indicate if Middle or Secondary School).Be sure to include THIRD MATHNOTATIONS ONLINE CONTEST in the subject/title of the email. I will accept registrations up to Fri October 9th (exceptions can always be…

• 
  Neoformix

• Twitter StreamGraph Supports Lists

  16 Nov 2009 | 11:22 am

  I have updated Twitter StreamGraphs to support the new twitter lists. You just enter a list in the standard format in the text box to see the graph for the latest 1000 tweets from all members of the list. The standard format looks like this: @scobleizer/web-innovators. The Twitter StreamGraph for the list @scobleizer/web-innovators (click to launch application)

• More Twitter ListMates

  16 Nov 2009 | 12:13 am

  In Twitter ListMates I introduced a name for the idea of people who are often grouped together on Twitter lists. The idea has value because listmates have been grouped together by multiple people who independently decided that those accounts are similar in some sense. Doing this type of analysis starting from my account, JeffClark, helped me find new people to follow. I have repeated the process for four other accounts to try and confirm that this technique is indeed useful. The results are shown below. For Robert Scoble (scobleizer) we get: guykawasaki mashable techcrunch kevinrose…

• Twitter ListMates

  12 Nov 2009 | 6:00 am

  In the recent post called Twitter List Profile Clouds I explored how the Twitter list names to which a person has been added can reveal how they are perceived across the twittersphere. Another interesting idea is that when somebody adds an account to a list they are implicitly defining a relation between that account and every other account on the same list. They are essentially making a declaration that all the members of the list share some characteristic. The name of the list usually offers a clue about how all the list members are related. So, for example, the fact that datavis and…

• Two Sides of the Same Story

  9 Nov 2009 | 3:27 am

  Jer Thorp has been doing some amazing work over the last couple of years. He just wrote an excellent post called Two Sides of the Same Story: Laskas & Gladwell on CTE & the NFL where he introduces a small visualization tool to look at the similarities and differences between two articles published in October about head injuries and the NFL. The articles are Game Brain, by Jeanne Marie Laskas and Offensive Play, by Malcolm Gladwell. The image below shows an example of what his tool can do. I have previously explored the idea of comparing and contrasting document pairs with my Document…

• Twitter List Profile Clouds

  8 Nov 2009 | 12:50 pm

  Twitter recently introduced the Twitter List feature which lets people define sets of user accounts that are related in some manner. The lists are given a name and can be followed by other people who are interested in seeing all the tweets from the accounts in the list. Popular twitter users such as Robert Scoble appear on thousands of lists - 3963 for Robert at this time. My twitter Id JeffClark, appears on a more modest 40 lists for comparison. The act of assigning someone to a list is a type of tagging operation and the name of the list gives a clue regarding how that person is regarded by…