A little humor for all of you who are grading or taking exams… [From failblog.org] [via Superpoop]
Fallacies, Flaws, and Flimflam it’s been good to know ya
At the end of 2008 the College Mathematics Journal will stop running its 20-year column “Fallacies, Flaws, and Flimflam.” The column was devoted to “mistakes, fallacies, howlers, anomalies, and the like”—usually found on student work. In honor of the departure of this entertaining column I submit the following FFF which was submitted as a solution…
Sharkovsky’s theorem
In this post I would like to share one of the most surprising, remarkable, and beautiful results in the study of discrete dynamical systems. It relates to an unusual ordering of the positive integers: First, some definitions. The basic object of study in a discrete dynamical system is the orbit. Let be a function from…
Facebook page for Euler’s Gem
I decided to create a Facebook page for my book, Euler’s Gem. We’ll see how it goes. I’m not convinced that people actually visit these pages more than once, but we’ll see. I’ll post reviews as they come in.
Is π the right constant?
In the November 3, 2001 issue of the Mathematical Intelligencer Bob Palais wrote an article called “ is wrong!” In it Palais does not assert that we have miscalculated the value of , just that many mathematical formulas would be more elegant if we had chosen a different value for our named constant—he thinks that…
Möbius bubble wrap
This week’s New York Times Magazine has an article called “The Year in Ideas.” One feature in the article is “Bubble Wrap That Never Ends,” by Vanessa Gregory. She writes about the popular Japanese keychain called Mugen Puchi Puchi. It has six small buttons on it, and pressing them simulates popping bubble wrap. The keychain…
KenKen
I just discovered a cool new Sudoku-like game called KenKen. A KenKen board is an nxn grid, and the object is to place the numbers 1 to n in each square subject to the following rules. Do not repeat a number in any row or column. The numbers in each heavily outlined set of squares,…
A new continued fraction for pi
I love continued fractions. The golden ratio: The square root of 2: The base of the natural logarithm: Pi: In the most recent American Mathematical Monthly (December 2008) Thomas J. Pickett and Ann Coleman, in their note “Another Continued Fraction for ,” present the following beautiful continued fraction in which the terms down the diagonal…
Four color theorem applets
The four color theorem is a beloved result with a long and fascinating history. The theorem says that four colors suffice to color any map so that no two bordering regions are the same color. The conjecture was made in 1852 by Francis Guthrie. After many, many failed proofs, the conjecture was finally put to…
Twittering Division by Zero
I’ve been on Twitter for a few months, posting unimportant details about my life. But I’ve decided to repurpose that service and make it another outlet for my Division by Zero blog. In case you are not aware, Twitter is a micro-blogging service that allows you to publish posts (“tweets”) of up to 140 characters at…
David Richeson: Division by Zero 