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IntMath Newsletter: Angular velocity, face numbers, WIRIS

By Murray Bourne, 31 Oct 2016

31 Oct 2016

In this Newsletter:

0. Ad blockers
1. Linear & angular velocity applet
2. Your face in numbers: Microsoft's Face Detection app
3. Resource: WIRIS Calc
4. Math movie: Conspiracy theories & math
5. Math puzzles
6. Final thought

0. Ad blockers

Most of us cannot imagine how we'd cope without Google, YouTube, Facebook and Twitter. What keeps all of these coming into our lives for free? It's the same thing that's kept magazine, newspapers, television and other news services alive for many years: advertising.

Yes, you can easily block the ads on Google, YouTube, Facebook and Twitter, but please consider the outcome if everyone does that. All those services — and IntMath as well — would disappear.

1. Linear & angular velocity applet

Linear and angular velocity applet

An object going around a circle has both an angular velocity (the amount of turn per time) and a linear velocity (the familiar distance per time).

I recently added a linear and angular velocity applet where you can explore this concept, on the Applications of Radian Measure page:

Angular velocity applet

2. Your face in numbers: Microsoft's Face Detection app

Face detection is a fast growing research area because of its many applications in the security arena.

Microsoft's face-detection app

Microsoft's Face Detection app is a lot of fun. You can upload any face picture and it will analyse the various parameters of the face (width between the eyes, nose and lips position, etc). It even takes a guess at the age of the person in the picture. For my picture, it was only a year or two out! (Ignore the "get started for free" button - that's for programmers.)

Face detection app

On that page there's also "Face verification" to detect if 2 photos are of the same person, and also video face analysis near the bottom.

This could make a motivating class project on data gathering and intepretation.

3. Resource: WIRIS Calc

Wiris computer algebra system

WIRIS Calc (which I reported on earlier) is now in beta. This simple to use online computer algebra system has a lot of promise in an increasingly competitive field.

It will solve problems in algebra, calculus and logic, and will also draw graphs.


You can also save your worksheet to your local computer, to the Cloud, or as a PDF. Here's the documentation.

4. Math movie: Conspiracy theories & math

As I write, the debate about which US election conspiracy theory to believe continues to rage.

Ramsey Theory - and conspiracies

From an early age, we look for patterns and usually the ones we find are actually there. But an interesting field of mathematics looks at how easy it is to find patterns just about anywhere, even where none were intended. This TED-Ed lesson explains how Ramsey Theory works.

The origin of countless conspiracy theories

If you can vote in this, the worst election in living memory, please do.

5. Math puzzles

a. Bus route problem: The earlier problem (in the 29 Aug 2016 Newsletter) has been solved! Narendrakumar got the correct number of bus routes.

b. Domino puzzle: The puzzle in the last IntMath Newsletter asked about the sum of the fractions formed by the tiles in a domino set.

There was only one attempt to solve it, by Bill, and he was correct. (He gave 2 answers using different assumptions. but his first answer addresses the original conditions of the puzzle.)

Dominoes solution

The first row gives us (0 + 1)/1 = 1

The second row is (0 + 1 + 2)/2 = 3/2

The third row is (0 + 1 + 2 + 3)/3 = 2

And so on.

New math puzzle


A sheep is placed in a circular fenced pen where it can chew grass all day. The farmer wants to make sure there is enough grass left in the pen for the following day, so she ties the sheep to one of the fence posts using a rope.

How long does the rope have to be so the sheep can only eat half of the grass?

You can leave your responses here.

6. Final thought: Responding

From the moment we're born, we start learning to respond to the things lfe throws at us. How much better off we'd all be if we saw each bad (and good) experience as a learning opportunity. It's all in our approach.

There's nothing in your life you can't learn from, if you respond with the right attitude. [Rick Warren]

Until next time, enjoy whatever you learn.

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