IntMath Newsletter: Derivative graphs, roller door problem, online math in remote India

By Murray Bourne, 05 Dec 2012

5 Dec 2012

In this Newsletter:

1. Derivative graphs interactive
2. Roller door problem
3. Online math education for Ajab, Gujurat
4. Math puzzles
5. Friday math movies
6. Final thought - candles

1. Derivative graphs interactive

Calculus can be a bit of a mystery at first. Explore these graphs to get a better idea of what differentiation actually means.

Derivative graphs interactive

2. Roller Door problem

Here's a real-life application of calculus posed by a roller door engineer.

I actually made an error when first writing the article. I should have done an estimation first, something I always preach. (My graph worked fine, so I thought all was good. I'd used the correct formula for the graph, but not for the integration.)

See: Roller Door problem

3. Online math education for Ajab, Gujarat

Students in Ajab village, India, enjoy a math lesson via Web conference from the US.

Online math education for Ajab, Gujarat

4. Math puzzles

(a) Last puzzle: The puzzle in the last Newsletter asked about the number of messages you can send using a flashlight.

The correct answer was 30 messages. People who got it correct and showed working were: Soutrik, Pradyut De, Guido, Nicos Mavrommatis, Thomas A Buckley and Rosa.

(b) New puzzle: What is the value of the following?

$\frac{1}{2}+(\frac{1}{3}+\frac{2}{3})$ $+(\frac{1}{4}+\frac{2}{4}+\frac{3}{4})$ $+(\frac{1}{5}+\frac{2}{5}+\frac{3}{5}+\frac{4}{5})$ $+...+(\frac{1}{100}+...+\frac{99}{100})$