Mathblogging.orgRecent Postshttp://www.mathblogging.org/scripts/feed.php2014-07-24T10:37:24-04:00No copyright asserted over individual posts; see original posts for copyright and/or licensing.Mathblogging.org Atom serializerMy notes on Khan Academy's SAT prep at You Do the Mathhttp://www.mathblogging.org/post/936122014-07-24T03:31:00-04:00MarkThis is a work in progress so we should cut the Khan Academy some slack. Even with that in mind, though, I'm seriously underwhelmed by the SAT prep materials up so far. I know their heart is in the right place, but from the skimpy selection to the low wattage instruction, there's just not that much here.<br /><br />I address the subject in more detail at the teaching site, You Do the Math, but I don't hit the bigger concern that I keep running into with these online learning ventures. As far as I can […]trigonometry-is-my-bitch:
Geometrical visualisation of a 4D...http://www.mathblogging.org/post/936102014-07-24T03:20:40-04:00Unknown<br/><br/>trigonometry-is-my-bitch:
Geometrical visualisation of a 4D shape from a 3D Perspective - The Tesseract
Hypercubes are shapes with n dimensions where n is greater than the 3 dimensions of a normal cube. The Tesseract, or the 4-cube, is a 4 dimensional hypercube.
where n is the dimensional number, in any hypercube:
vertices = 2^n
edges = n(2^n-1 )
faces = 2^n-3(n-1)n
1809http://www.mathblogging.org/post/936072014-07-24T02:30:00-04:00Mathematical Association of America1809 = 3 x 3 x 3 x 67.<br /><br />1809 is the sum of the first 26 palindromes (A046489).<br /><br />1809 is the sum of the first 17 primes whose indices are primes (A083186).<br /><br />1809 is a non-palindromic balanced number; the first and last half of its digits have the same sum (A145808).<br /><br />1809 is a multiple of 9 that contains 9 in its decimal representation (A121029).<br /><br />1809 is 3421 in base 8. It is 809 in base 15.<br /><br />1809 divides 373 - 1.<br /><br /><br />Source: OEISCompletamento del quadratohttp://www.mathblogging.org/post/936082014-07-24T01:47:35-04:00Angelo StellaCompletamento del quadrato. Parabola e circonferenza. Spiegazione :lol: © 2014, Angelo Stella. All rights reserved.
Euclid in a Taxicab: Sparse Blind Deconvolution with Smoothed $\ell_1/ell_2$ Regularizationhttp://www.mathblogging.org/post/936062014-07-24T01:00:00-04:00IgorLaurent Duval just sent me the following:<br />Dear IgorNuit Blanche is a nest of choice for many sparsities. The ones of concern here are those approximated by an $l_1/l_2$, or Taxicab/Euclidean norm ratio, which was already covered in some of your posts: http://nuit-blanche.blogspot.fr/2012/04/compressive-sensing-this-week.htmlhttp://nuit-blanche.blogspot.fr/2012/03/old-and-new-algorithm-for-blind.htmlhttp://nuit-blanche.blogspot.fr/2008/05/cs-kgg-explanation-of-l0-and-l1.html We propose
[…]Decimal Mistake in the Newshttp://www.mathblogging.org/post/936042014-07-23T23:07:13-04:00ΞDecimal points are small, and so easy to lose. And it appears that many of them were lost on FAFSA (Free Application for Federal Student Aid) forms, which is NOT a place that you would want incorrect data. According to an official document from July 18, people filling out the form were supposed to round monetary […]Coherent population forecasting using Rhttp://www.mathblogging.org/post/936052014-07-23T22:03:01-04:00Rob J HyndmanThis is an example of how to use the demography package in R for stochastic population forecasting with coherent components. It is based on the papers by Hyndman and Booth (IJF 2008) and Hyndman, Booth and Yasmeen (Demography 2013). I will use Australian data from 1950 to 2009 and forecast the next 50 years. In demography, “coherent” forecasts are where male and females (or other sub-groups) do not diverge over time. (Essentially, we require the difference between the groups to be […]Large cardinals need not be large in HODhttp://www.mathblogging.org/post/936032014-07-23T21:50:22-04:00Joel David Hamkins[bibtex key=ChengFriedmanHamkins:LargeCardinalsNeedNotBeLargeInHOD] Continue reading →#70Days Must read "Why Do Americans Stink at Math"http://www.mathblogging.org/post/935972014-07-23T21:44:00-04:00Beth FergusonI read an excellent article today ... Why Do Americans Stink at Math? Please, read it!<br /><br />Several years ago I read the book, Innumeracy: Mathematical Illiteracy and Its Consequences by John Allen Paulos. It was interesting to see documented the very thing I had heard too many times. Parents would say, "I was never good at math either. I can't even balance my checkbook." Not many people would admit to not being able to read the newspaper, but parent after parent […]Redefining Mathematics Education #ADE2014 Showcasehttp://www.mathblogging.org/post/935962014-07-23T21:18:44-04:00Kyle PearceAnother post from Tap Into Teen Minds. Enjoy!<br />
Watch my Apple Distinguished Educator Showcase from the 2014 Global Institute in San Diego, California on Redefining Mathematics Education.
The post Redefining Mathematics Education #ADE2014 Showcase appeared first on Tap Into Teen Minds."__BL" : Education's Obsession With Labelshttp://www.mathblogging.org/post/936022014-07-23T21:15:00-04:00Nat Banting<br />Last week there was an interesting twitter discussion on the nature of projects versus the nature of problems.<br />@dandersod @samjshah @k8nowak @leslie_su76 How is Mega M&M a project rather than a problem?— Dan Meyer (@ddmeyer) July 17, 2014 It occurred with specific reference between the differences of PBL (project-based learning) and PrBL (problem-based learning). If you follow this blog or scan the provided tags you will find PBL does occupy some space here. There is also a large amount of
[…]Big grids in outerplanar strict confluent graphshttp://www.mathblogging.org/post/935982014-07-23T20:50:58-04:00UnknownI was wondering whether the outerplanar strict confluent drawings I studied in a Graph Drawing paper last year had underlying diagrams whose treewidth is bounded, similarly to the treewidth bound for the usual outerplanar graphs. The confluent graphs themselves can't have low treewidth, because they include large complete bipartite graphs, but I was hoping that a treewidth bound for the diagram could be used to prove that the graphs themselves have low clique-width. Sadly, it turns out not to […]trigonometry-is-my-bitch:
Geometrical visualisation of a 4D...http://www.mathblogging.org/post/936002014-07-23T20:40:55-04:00Unknown<br/><br/>trigonometry-is-my-bitch:
Geometrical visualisation of a 4D shape from a 3D Perspective - The Tesseract
Hypercubes are shapes with n dimensions where n is greater than the 3 dimensions of a normal cube. The Tesseract, or the 4-cube, is a 4 dimensional hypercube.
where n is the dimensional number, in any hypercube:
vertices = 2^n
edges = n(2^n-1 )
faces = 2^n-3(n-1)n
Black Moonhttp://www.mathblogging.org/post/935992014-07-23T20:22:40-04:00XanderI finished my masters a little more than a year ago and am starting a Ph.D. in two months. In the intervening year, I have done a little research, some teaching, and made the (very) occasional post here. I have … Continue reading →One quote that tells you everything you need to about Florida's culture of charter school oversighthttp://www.mathblogging.org/post/935932014-07-23T20:11:00-04:00MarkFrom the Sun-Sentinel's previously mentioned profile of Steve Gallon III [emphasis added].The schools’ financial team began to caution the boards against overspending, flag certain payments, and raise concerns about Gallon’s seemingly unchecked authority.<br /><br />“I started warning board members,” said [Katrina] Lunsford, the financial manager.<br /><br />She also said: “He, from an overall standpoint, just started taking charge and taking over.”<br /><br />Records show the boards at times responded with
[…]Discrete wiskundehttp://www.mathblogging.org/post/935942014-07-23T19:10:00-04:00Willem van Ravenstein <br />voorkennishet binomium van Newtonvolledige inductierecursieve formulesrekenkundige rijenmeetkundige rijenDat was nog een heel gedoe...<br />#July2014Challenge: The other SBGhttp://www.mathblogging.org/post/935892014-07-23T19:05:00-04:00Shelley CarranzaI had to work today, so I figured I would go for an easy blogpost. I am part of a blogging challenge to blog everyday in July, put together by druin. I figured an easy blogpost would be one where I am sharing one of the many amazing teaching resources or strategies that have been shared with me over the years. Enter SBG.<br /><br />No, I don't mean Standards Based Grading. When I first started reading blogs I saw SBG plastered all over blog links. This was really confusing,
[…]On This Day in Math - July 24http://www.mathblogging.org/post/935952014-07-23T19:00:00-04:00Pat Ballew<br /><br /><br />In mathematics the art of proposing a question must be held of higher value than solving it. ~Goerg Cantor<br /><br />Today is the 205th day of the year; there are 205 pairs of twin primes less than ten thousand. *Number Gossip <br /><br />EVENTSIn 1673, Edmund Halley entered Queen's College, Oxford, as an undergraduate. Halley had attended the prestigious St. Paul's school, where in 1671, he was appointed captain, a position resembling today's student body president. He was an excellent student, and by the […]U.S. senator appears to have plagiarized his master’s thesishttp://www.mathblogging.org/post/935912014-07-23T18:38:33-04:00Ivan OranskyA Democratic senator from Montana, John Walsh, is the latest high-profile politician to face plagiarism charges. The New York Times reports: …one of the highest-profile credentials of Mr. Walsh’s 33-year military career appears to have been improperly attained. An examination of the final paper required for Mr. Walsh’s master’s degree from the United States Army […]Flowhttp://www.mathblogging.org/post/935902014-07-23T18:36:16-04:00UnknownI have been doing a fair amount of yoga down here in NOLA. It was part of my commitment to myself that I would find a way to remain active during my stay here. (Especially with all the excellent fried cuisine and cocktails, it seemed a real priority to exercise.) I signed up for an unlimited introductory deal, and I have been doing an hour of fairly rigorous yoga every weekday without missing a beat. At first, because I had been away from the mat for so long (months, really), I had a hard time […]Wildcard Skepticismhttp://www.mathblogging.org/post/935852014-07-23T18:19:37-04:00Eric SchwitzgebelMight there be excellent reasons to embrace radical skepticism, of which we are entirely unaware? You know brain-in-a-vat skepticism -- the view that maybe last night while I was sleeping, alien superscientists removed my brain, envatted it, and are now stimulating it to create the false impression that I'm still...> plot( polyroot(choose(131,14:29)) ,pch=19,col='red')
>...http://www.mathblogging.org/post/935872014-07-23T18:16:00-04:00Unknown<br/> 29<br/><br/> <br/> 39<br/><br/> <br/> 59<br/><br/> <br/> 79<br/><br/> <br/> 99<br/><br/> <br/> 119<br/><br/> <br/> "139"<br/><br/> > plot( polyroot(choose(131,14:29)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:39)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:59)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:79)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:99)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:119)) ,pch=19,col='red')
> plot( polyroot(choose(131,14:139)) ,pch=19,col='red')
ABC in Sydney [guest post #2]http://www.mathblogging.org/post/935922014-07-23T18:14:23-04:00xi'an[Here is a second guest post on the ABC in Sydney workshop, written by Chris Drovandi] First up Dennis Prangle presented his recent work on “Lazy ABC”, which can speed up ABC by potentially abandoning model simulations early that do not look promising. Dennis introduces a continuation probability to ensure that the target distribution of […]Eric Kaplan, Comedian-Philosopher, Has a New Blog.http://www.mathblogging.org/post/935862014-07-23T18:11:56-04:00Eric SchwitzgebelEric Kaplan, who overlapped with me in grad school at Berkeley but who is now much more famous as a comedy writer for Big Bang Theory, Futurama, and several other shows, has been cooking up weird philosophical-comical blog posts since March at his Wordpress blog here. Check it out!the sum of two angles of a triangle geometric proofhttp://www.mathblogging.org/post/935882014-07-23T17:18:11-04:00Unknownnewest proofthe sum of two angles of a trianglehttp://www.mathblogging.org/post/935812014-07-23T16:47:30-04:00Unknownnewest propositionAnnouncing Wolfram SystemModeler 4http://www.mathblogging.org/post/935832014-07-23T16:28:57-04:00Roger GermundssonToday we are proud to announce the release of Wolfram SystemModeler 4. For SystemModeler 4, we have expanded the supported model libraries to cover many new areas. We’ve also improved workflows for everything from learning the software to developing models to analyzing and deploying them. People have been using SystemModeler in an astonishing variety of [...]Donna Kalinowsky on Berkshire Community Collegehttp://www.mathblogging.org/post/935792014-07-23T16:14:34-04:00Frank MorganI am excited about spending part of my sabbatical this fall at Berkshire Community College. I’d say that community colleges are where education meets the future. It looks like next year for the first time a majority of US college students will be at community colleges. So far everyone I’ve met loves the college and […]Common Core Goes to Collegehttp://www.mathblogging.org/post/935842014-07-23T16:11:00-04:00Bruce YoshiwaraThe New America Foundation’s position paper by Lindsey Tepe gives recommendations for how higher education can support the Common Core State Standards. However, this paper and related articles in the Chronicle and Hechinger Report miss the most important way for higher education to support the CCSS, namely, to work to repair or ameliorate the existing flaws in the CCSS. position paper<br />An implicit assumption in Tepe's paper is that the CCSS have successfully captured what all
[…]Math T-shirthttp://www.mathblogging.org/post/935762014-07-23T16:03:03-04:00Maiu