Column
- Math
Testing for Divisibility
The crisp new dollar bill that I have just taken from my wallet bears the serial number 24598176. It’s easy to tell that the number is exactly divisible by 2 but not by 5. Is it divisible by 3? by 4? by 11? In a 1962 Scientific American article, Martin Gardner noted that during the […]
- Math
Jazzing Up Euclid’s Algorithm
Earlier this year, the journal Computing in Science & Engineering (CISE) published a list of the top 10 algorithms of the century (see http://computer.org/cise/articles/Top_Algorithms.htm). “Computational algorithms are probably as old as civilization,” Francis Sullivan of the Institute for Defense Analyses’ Center for Computing Sciences in Bowie, Md. noted in an editorial in the January/February issue […]
- Math
A Minimal Winter’s Tale
The organizers of the Breckenridge snow sculpture championships in Colorado must be getting used to having a mathematical element in their annual competition. A simple version of Enneper’s surface just before (above) and just after (below) it self-intersects. The award-winning snow sculpture of Enneper’s surface. For the second year in a row, a team assembled […]
- Math
Home Runs and Ballparks
When baseball slugger Mark McGwire of the St. Louis Cardinals hit his record-breaking, 62nd home run on Sept. 8, 1998, the ball barely passed over the left field fence at Busch Stadium in St. Louis. The same hit would not have been a home run at, say, Fenway Park in Boston. This episode suggests an […]
- Math
Home Runs and Ballparks
When baseball slugger Mark McGwire of the St. Louis Cardinals hit his record-breaking, 62nd home run on Sept. 8, 1998, the ball barely passed over the left field fence at Busch Stadium in St. Louis. The same hit would not have been a home run at, say, Fenway Park in Boston. This episode suggests an […]
- Math
Taxicab Numbers
Curious properties sometimes lurk within seemingly undistinguished numbers. Consider the story concerning Indian mathematician Srinivasa Ramanujan (1887–1920). His friend G.H. Hardy (1877–1947) once remarked that the taxi by which he had arrived had a “dull” number–1729, or 7 x 13 x 19. Ramanujan was quick to point out that 1729 is actually a “very interesting” […]
- Math
Dangerous Problems
Some mathematical problems are easy to describe but turn out to be notoriously difficult to solve. Nonetheless, despite their reputed difficulty and repeated warnings from those who had failed to solve them in the past, these infamous problems continue to lure mathematicians into hours, days, and even years of futile labor. Billiard-ball trajectory after 15 […]
- Math
Dangerous Problems
Some mathematical problems are easy to describe but turn out to be notoriously difficult to solve. Nonetheless, despite their reputed difficulty and repeated warnings from those who had failed to solve them in the past, these infamous problems continue to lure mathematicians into hours, days, and even years of futile labor. Billiard-ball trajectory after 15 […]
- Math
Dangerous Problems
Some mathematical problems are easy to describe but turn out to be notoriously difficult to solve. Nonetheless, despite their reputed difficulty and repeated warnings from those who had failed to solve them in the past, these infamous problems continue to lure mathematicians into hours, days, and even years of futile labor. Billiard-ball trajectory after 15 […]
- Math
Dangerous Problems
Some mathematical problems are easy to describe but turn out to be notoriously difficult to solve. Nonetheless, despite their reputed difficulty and repeated warnings from those who had failed to solve them in the past, these infamous problems continue to lure mathematicians into hours, days, and even years of futile labor. In a presentation this […]
- Math
The Math Game
The television game show Who Wants to Be a Millionaire regularly attracts a huge audience. Can a mathematical game show hold its own against such competition–especially without lifelines, dramatic lighting effects, precarious chairs for contestants, and Regis Philbin as host? Probably not, but it can still be great fun. More than 200 mathematicians and students […]
- Math
Turn of the Screw
“What we are told about Archimedes is a mix of a few hard facts and many legends,” Sherman Stein of the University of California, Davis notes in his book Archimedes: What Did He Do Besides Cry Eureka? A three-bladed Archimedes screw. Courtesy of Chris Rorres. I was reminded of that statement when my son Kenneth […]
