# 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. |

## 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. |

## 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?

You can respond in the comments.

## 5. Friday math movies

Well-known mathematician Steven Strogatz talks about how flocking behavior naturally occurs - and some mathematical reasons for it. |

Meet 12-year-old Amy O'Toole presenting a scientific paper that starts, "Once upon a time..." |

## 6. Final thought - candles

This quote suggests it's up to us to make sure we know what's going on.

If you're not lighting any candles, don't complain about being in the dark. [Anon]

Until next time, enjoy whatever you learn.

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