The classic birthday problem asks how many people are required to ensure a greater than 50% chance of having at least one birthday match, meaning that two or more people share a birthday. The surprisingly small answer, assuming that all birthdays are equally likely and ignoring leap years like 2012, is 23 people.
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What’s the (implicit) equation for “equation”?
See for yourself with this inverse graphing calculator.
APPROXYMOTION by Peter A Vikar
[vimeo url=http://vimeo.com/40641882]
Peter’s site is full of beautifully stark geometric/topological art
Classic maths books reset with LaTeX on Project Gutenberg
I was going to save this for an Aperiodical Round Up but it’s such a good thing I thought I’d post it straight away. Project Gutenberg has moved on from offering just plain-text transcriptions of books: volunteers have been outstandingly generous with their time and produced LaTeX versions of many maths books, producing versions that are considerably more readable and resemble the original editions much more closely.
Not all the books in that list have been converted to LaTeX yet. Of those that have, GH Hardy’s A Course of Pure Mathematics leaps out as a good place to start. Compare it with this book still in HTML format to see the difference.
(via reddit)
Inclusion and Exclusion and the new GMAT
Dublin native Colm Mulcahy has been in the Department of Mathematics at Spelman College since 1988. His interests include algebra, number theory, geometry and mathematical card principles and effects. Follow him on Twitter at @CardColm and also check out @WWMGT.
The last question, under the heading “Two-Part Analysis”, at the end of this NYT article (from July 2011) on the new GMAT seems to be deliberately worded in a way that forces one to read and think very carefully.
It takes a while to even process the question as it’s asked! I’m assuming that was intentional.
I’m curious how “they” intended people to solve this. Exclude impossible answers until only one is still Included? I guess so.
Introducing The Aperiodical
You may have noticed a new look here on Travels in a Mathematical World. For a while this blog was designed to look like a page from my website peterrowlett.net, but now it is different. This is because I have joined Katie Steckles and Christian Perfect in a collaborative blogging endeavour we’re calling The Aperiodical.
A launch post over at The Aperiodical says
The Aperiodical is a new maths magazine/blog aimed at people interested in mathematics who want to read stuff. We post news stories related to maths, opinion pieces, interesting things we’ve found, accounts of monthly MathsJams, maths videos, and feature articles, as well as posts from our own blogs. We also host the Carnival of Mathematics, a monthly blogging carnival.
We’ve picked today to launch as it is the anniversary of Felix Klein’s birth, and we offer some shiny Klein goodies to get started. Matt Parker and Katie Steckles investigate the amazing surface which bears his name in a video ‘Top N Facts about the Klein Bottle‘.
This got us wondering – what did Klein do apart from that ever famous bottle? Christian, Katie and I investigated and found an interesting career both in research mathematics and other contributions to the discipline, including excellent teaching, editorship of a famous journal and encyclopaedia, acting on a strong interest in school teaching and promoting mathematics to the general public. We wrote up what we found in ‘Klein: outside the bottle‘.
But we aren’t just writing our own posts on the site. We’re also keen to publish reports, exposition, videos, or anything mathematical and interesting that you want to share. Recently we’ve carried interesting pieces by Andrew Taylor offering an application of Grime Dice to electoral reform (as heard on the BBC’s Material World) and Paul Taylor on how he devised the Hilbert’s Space-Filling Crossword on our Features feed. If you’d like to write something please get in touch.
You can find out more about the approach we’re taking with The Aperiodical, view pages and get RSS feeds for all our different types of post, and much more by reading the launch post: The Aperiodical.
Manchester MathsJam April 2012 Recap
The turnout this month was slightly lower than usual, but many of our regulars were there and we had the chance to have some good discussions and really get into things.