Math Boo-yah

I just got done with a round of midterms. I'm always fascinated by the scribbles students write on their test. My favorite scribble among the recently corrected is a student that got a little over zealous when checking his answer. I'm always harping on students to check. I say it so many times I'm even sick of hearing it. Well, I finally reached someone. Boo-yah!

Probability Problem

Lee found this nice problem in the Minitab manual that accompanies "Elementary Statistics" by Mario F. Triola. The problem posed is:

Two points along a straight stick are randomly selected. The stick is then broken at these two points. Find the probability that the three pieces can be arranged to form a triangle.

pic by flowers & machinery

Geek of the Week: Colleen

Listen to this:


I think the geekiness explains itself. If you need more convincing...Colleen took time over vacation to memorize it, just so she could recite it for Sue and me after break. Not only is it geeky, it's sweet and geeky. Thanks for making my pi-day, Colleen!

100 Greatest Theorems

Jay sent me an unbelievable link. Paul and Jack Abad presented this list of 100 greatest theorems at a math conference in 1999. Their criteria for the greatness of a theorem was
1) the place the theorem holds in the literature
2) the quality of the proof
3) the unexpectedness of the result
I had fun looking for my favorites: denumerability of the rationals, the non-denumerability of the continuum, and the incompleteness theorems. Jeff and Lee will be happy to see that the infinitude of the primes made it (#11). The list has dates for all the theorems, and links to proofs for some of them. Any guess as to what's number 1?

pic from Boston Bill

Using Selectricity

I'm entering a unit on elections in my Math for Liberal Arts class. There are a lot of slick tools out there to run online polls like PollDaddy. I was having trouble finding any tool that allowed user's to fully order their preferences... until Selectricity. It's a really great tool, particularly if you are studying elections. Check out this poll, it allows you to see current results, and the current winner under a number of common election systems: Borda, Condorcet, etc. Anyone can create an election without registering. For more extensive security measures, register for a full account. All free!

pic by Enrico Fuente

19th Annual Tunxis Math Contest

Rob Clark is hosting his annual Math melee. You can problem solve for money. Here are the details.

Tunxis Annual Math Contest: Friday, April 3, 2009 from 12:00 – 2:00 p.m. in Room 6-201. Cash Prizes Awarded! $250, $150, $100 for 1st, 2nd, and 3rd.
OPEN TO ANY STUDENT CURRENTLY ENROLLED IN ANY COURSE AT TUNXIS. QUESTIONS ON THE EXAM ARE MOSTLY ALGEBRAIC. THERE IS NO TRIG OR CALCULUS ON THE EXAM. SIGN UP WITH R. CLARK IN OFFICE F-32. SAMPLE EXAMS AVAILABLE IN OFFICE F-32.

My New Favorite Puzzle: Tentaizu

I found a new puzzle. New to me anyway. It's called Tentaizu. I found it in the in-flight magazine on the way home from vacation. Btw, Southwest's magazine has the best puzzle section that I've ever seen. Not a reason to buy a ticket, but a definite perk. Anyway, I was completely charmed by this game. I thought we would play one this week. Maybe if we get excited we can try to automate a solution technique. I also tried to find a website that generates these like those I've found for Sudoku and KenKen. No luck.

Here are the instructions from Southwest's magazine:
In each of the grids on this page, stars are
hiding in 10 of the 49 squares. Your task is
to determine the positions of the stars. The
numbers in the grid provide clues: A number
in a square indicates how many stars lie next
to the square—in other words, how many
adjacent squares (including diagonally adjacent
squares) contain stars. No square with
a number in it contains a star, but a star may
appear in a square with no adjacent numbers.