Posts tagged ‘math’
Fun with Python’s decimal library
January 28th, 2012 at 9:02 pm by Dr. Drang
You’ve probably run across a link to this cute math fact in the past few days: [\frac{1}{998001} = 0.000001002\ldots100101102\ldots900901902\ldots999\ldots] This relatively simple fraction generates a decimal number that contains, in order, every three-digit sequence from 000 to 999 (except, sadly, 998). Pretty cool. If it’s true. I don’t want to be cynical or disparage the…
My .octaverc
November 29th, 2011 at 9:22 am by Dr. Drang
Since I mentioned my ~/.octaverc file a couple of posts ago, I might as well show you the whole thing. It’s not much. The ~/.octaverc file is one of those dotfiles so beloved by Unix users. It’s a set of Octave commands that are run at the beginning of every session to customize the environment…
Let’s twist again
September 29th, 2011 at 1:30 pm by Dr. Drang
Sunday night, my wife and I heard a muffled bang that seemed to be coming from our garage. Expecting to find that a shovel had fallen off the wall rack and into my car, I went out to take a look. Nothing. Maybe the noise came from outside? I pushed the garage door button to…
Integrality of the game
September 22nd, 2011 at 11:35 pm by Dr. Drang
I started using the Yahoo! Sports mobile site a few days ago to keep track of scores and standings. I’ve been using SportsTap for ages, but its server connection has been unreliable lately, so I thought I’d try something else. Overall, Y! SPORTS1 is a snappy, easy-to-navigate mobile web app with a nice layout. But…
To infinity and beyond
September 8th, 2011 at 9:59 pm by Dr. Drang
Here’s a math problem my sixth-grader came home with last night. You have a bottomless pit with [x] marbles in it. Two of the marbles are black. You reach in and pull out two marbles at random. If [p(x)] is the probability that both marbles are black, what is [\sum_{x=3}^\infty \;p(x)] I sure don’t remember…
PCalc 2.4.1
August 5th, 2011 at 11:50 pm by Dr. Drang
A new version of PCalc hit the App Store today. The new feature is support for hardware keyboards, which I’m sure is a big improvement for a certain class of user. I don’t happen to be in that class—no iPad, no hardware keyboard—but because it’s been a year since my last PCalc post and there’ve…
Pendulum patterns
May 13th, 2011 at 10:47 pm by Dr. Drang
It was on Boing Boing and Kottke, so I’m sure you’ve seen this video of 15 tuned pendulums. The pendulum lengths are set so longest pendulum swings through 51 cycles per minute, the second-longest 52 cycles per minute, and so on up through 65 cycles per minute. As we showed in this post a couple…
The unreasonable effectiveness of mathematics
March 27th, 2011 at 2:25 am by Dr. Drang
My family and I are on vacation in Maui. There was a contest on the flight here from SFO a couple of days ago: Guess the exact time (to the nearest second) at which the plane would reach the halfway point of the trip. The crew gave out a lot of information about airspeed, distance,…
Oil can what?
February 12th, 2011 at 3:38 pm by Dr. Drang
I’ve been working on a nonlinear finite element program for the past week or so, and to shake out the bugs, I run it on a few test problems. One of my favorites is an example of snap-through buckling. It’s a simple little toggle structure with surprisingly rich behavior. The toggle looks like this: Two…
Coke cans, pull-tabs, and the class struggle
January 8th, 2011 at 3:45 pm by Dr. Drang
Yesterday, my wife sent me a link to this video. Bill Hammack, the self-styled Engineer Guy, has several cute videos like this posted on his web site, his YouTube channel, and his Facebook page. I think I saw one of them—the one where he takes a copier apart—on Boing Boing many months ago. Hammack’s an…
