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IntMath Newsletter: 3-D conics, interactives, March math

By Murray Bourne, 12 Mar 2012

12 Mar 2012

In this Newsletter:

1. Interactive 3-D conic sections graph
2. List of math interactives on
3. Special math events in March
4. Math Puzzles
5. Recent popular tweets
6. Friday math movies
7. Final thought: the greatest mistake

1. Interactive 3-D conic sections graph

Interactive 3D conic graph Here's a new 3-D interactive graph. You can use it to see how we get circles, ellipses, parabolas and hyperbolas from intersecting a double cone by a plane.

Interactive 3-D conic sections graph

2. List of math interactives on

Math interactives, including Math of Beauty Flash app I recently compiled a list of all the math manipulatives on These interactives are designed to help users understand math concepts through exploring.

Here they all are:

List of math interactives on

3. Special math events in March

a. Pi Day (14 Mar)

The number pi = 3.141592... arises in many different fields of mathematics, not just in circles!

Mar 14 (3.14) is celebrated as Pi Day. Meanwhile, some mathematicians think we should drop pi.

Researchers Yee and Kondo claim to have calculated Pi to 10 trillion digits on 17 Oct 2011.

b. Brain Awareness Week (12 to 18 Mar, 2012)

Brain Awareness Week aims to promote the public and personal benefits of brain research. It's organized by the Dana Alliance for Brain Initiatives and Society for Neuroscience

c. Expanding Your Horizons

The mission of Expanding Your Horizons Network is to encourage young women to pursue science, technology, engineering and mathematics (STEM) careers. This organization is quite active around International Women's Day (8th Mar).

You may have noticed Google used the following image on its home page on that day:

IWD Google Doodle
[Image source: Google]

d. Birthdays

Here are some mathematically significant March birthdays:

  1. Jules Antoine Lissajous, French mathematician, famous for the interesting curves called Lissajous Figures (born 4 Mar 1822)
  2. Gerardus Mercator, map maker, known for the Mercator Projection world map (born 5 March 1512)
  3. Albert Einstein (born 14 Mar 1879)
  4. René Descartes, mathematician and philosopher, developer of the cartesian x-y coordinate system (born 31 Mar 1596)

4. Math Puzzles

There were plenty of responses to the puzzle I presented in the last IntMath Newsletter about Egyptian fractions.

The correct answer, 1/2 + 1/3 + 1/78, was given by Don, Tomas, Laureli, Greg, Arun, George and Saran.

Special mention goes to to Francis and Sivy who were correct, but also showed the thinking behind their answers.

New puzzle: A man asked a zookeeper how many beasts and how many birds there were in his zoo. The zookeeper (a frustrated mathematician), answered, "There are 30 heads and 100 feet."

How many animals and birds were there? Please respond here.

5. Recent popular tweets

These tweets got a lot of response on Twitter:

  1. Here's a list of free math lectures: 100 Incredible Open Lectures for Math Geeks (the link has since gone down!)
  2. This one is good for Pi Day:
    A pizza with radius "z" and height "a" has volume pi*z*z*a.

Follow IntMath on Twitter!

6. Friday math movies

math-based music (a) The world's ugliest music

All music has a mathematical framework, but some music starts with a math concept. Here's an example.

Friday math movie: The world's ugliest music


(b) How to make choosing easier

Sheena Iyengar gives plenty of examples in this talk where we learn when it comes to choices, less is more. This video has many implications for more effective teaching.

Friday math movie: How to make choosing easier

vi hart

(c) Vi Hart Visual Multiplication and 48/2(9+3)

This short video explores an alternate way to do multiplication.

Friday math movie: Vi Hart Visual Multiplication and 48/2(9+3)

7. Final thought: the greatest mistake

Mathematics, like most activities involving problem solving, requires us to get into it and get our hands dirty - and of course, learn by making mistakes.

The following gem comes from American writer, publisher, artist, and philosopher Elbert Hubbard.

The greatest mistake you can make in life is to be continually fearing you will make one. [Elbert Hubbard]

Until next time, enjoy whatever you learn.

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