## The IntMath Newsletter – 14 Mar 2008 – Pi Day

[14 Mar 2008]

1. Pi Day
2. Math tips – Functions and Factoring
3. Latest poll
4. From the math blog

### 1. Pi Day

March 14th was chosen as Pi Day since 3/14 gives us the first 3 digits of pi (π = 3.14159265358979…).

Pi has many real world uses:

• Lengths, areas and volumes of curved surfaces in manufacturing.
• Electricity
• Statistics, where it is used in the equation describing the the standard normal curve.
• Passenger jets fly along arcs of great circles (rather than in straight lines). The calculation involves pi.
• ‘White noise’ is included in simulations (including computer games) to give more realism. Pi is involved in white noise.

Did you know…?

• π is actually pronounced “pee” (use this in class only if your math teacher has a sense of humour… )
• The Greek letter “pi” (π) was chosen around 300 years ago. It stands for “perimeter”.
• The Egyptians and the Babylonians (3000 years ago) knew that if you divide the circumference of any circle by its diameter, you get a number just over 3.
• The Greek mathematician Archimedes worked out that pi is just less than 22/7 in the 2nd century BCE.
• The current best known decimal approximation for pi has over a trillion digits.
• Learning the digits of pi: The record for the number of digits correctly learned is around 68,000. It took the Chinese guy over 24 hours to recite all 68,000 of them.

Here’s a trick to impress your friends. You can learn the first 15 digits of pi using the number of letters in each word of the following sentence:

How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics.

Happy Pi Day.

### 2. Math Tips

a. Functions are not hard, just written badly:
Many math concepts are hard because they are written in a confusing way. When we write a(b + c) we take it to mean multiply and we get ab + ac.

But if we have a function f(x) and write f(b + c), it does not mean fb + fc.

There are more examples about bad math notation and my suggested solution at Towards more meaningful math notation. I’d love to hear your comments on what I am proposing there.

b. Factoring trinomials using grouping:
A trinomial is an expression like 6x2 + x − 12.

To factor this trinomial means to express it in the form (3x − 4)(2x + 3).

A lot of students struggle with this process because of all the possible factors of the numbers involved. For example, 12 has factors 1, 2, 3, 4, 6, 12. But factoring does not have to be so hard. Check out Factoring Trinomials for an easy method involving grouping.

### 3. Latest Poll

It was a surprise to me that the highest number of responses went to doing algebra at 39% and the least liked was doing geometry at 9%. This is intriguing because most students I know dislike algebra more than anything else in math. Do you have a comment on this? Please go to Algebra is the favorite math activity and leave your thoughts.

Latest poll: Do you have a computer in your math classroom? Please vote on this issue on any page in Interactve Mathematics.

### 4. Latest on the Math Blog

a) Friday math movie – Pi Day
As today is Pi Day, the featured movie this week is the movie Pi.

b) Algebra is the favorite math activity
What is your favorite math activity? Do you agree with these poll results?

c) Visual statistics – the madness of consumerism
Here’s a brilliant way to express statistics in visual form. Each vast photograph is a collage of smaller photographs that depict the state of American consumerism.

d) Friday Math Movie – Fractals
Here’s a restful yet inspiring movie featuring fractals and great music.