# IntMath Newsletter: hyperbolas, Pixar, PhotoMath

By Murray Bourne, 25 Nov 2016

25 Nov 2016

In this Newsletter:

1. Interactive hyperbola graphs

2. Pixar in a box

3. Resource: PhotoMath

4. Math movie: Teach for Mastery

5. Math puzzles

6. Final thought: beliefs

## 0. Gratitude

It's the season for giving thanks, so here goes. For me, the greatest thing to be grateful for is my well-rounded and fair education. It was very sad to read about the children of Mosul who were being indoctrinated with a corrupted curriculum while ISIS was in charge. Most kids stayed away, being denied a vital education.

On with the Newsletter.

## 1. Interactive hyperbola graphs

## 2. Pixar in a box

There are a lot of interesting applications of mathematics to learn from Pixar in a Box. From the Khan Academy site:

Pixar in a Box is a behind-the-scenes look at how Pixar artists do their jobs. You will be able to animate bouncing balls, build a swarm of robots, and make virtual fireworks explode. The subjects you learn in school — math, science, computer science, and humanities — are used every day to create amazing movies at Pixar.

In the |

## 3. Resource: PhotoMath

PhotoMath is a clever iOS and Android app. You point your camera at an algebra question and it will solve it for you, including giving you the steps. It reads (neat) handwriting, and in my tests, was able to handle questions involving integrals, square roots and trigonometry. |

Search for PhotoMath on your phone or tablet in the App Store or Play Store. It's **free** until the end of November.

**Disclaimer 1: **IntMath has no connection with PhotoMath.

**Disclaimer 2: **PhotoMath, like all such computer-based math solving tools, should only be used to check your own work (which helps you to learn) - NOT to simply solve the homework for you (which usually results in your never knowing it).

## 4. Math movie: Salman Khan - Teach for Mastery

I once taught a class of pre-service primary school teachers. Many of them were not at all confident in mathematics generally, and certainly not at the level they were going to be teaching (decimals, fractions, money, units and so on).

I decided to use a mastery testing approach with this class. Students were given a series of quizzes throughout the semester, and they needed to obtain 80% to pass each one, and couldn't go on until they had "mastered" the earlier ones. They were given as many attempts as they needed. The test questions were taken from Year 5 and Year 6 primary school mathematics text books. While many students were initially unhappy about having to go through such a process, by the end of the semester they could see the point, and were much more confident (and competent) in the math they they would teach in the future.

## 5. Math puzzles

The puzzle in the last IntMath Newsletter asked about the length of rope needed to allow a sheep to eat half of a circular pen of grass.

There was one correct solution and it was well done by Gerard. (I added some images so Gerard's answer would be easier for you to follow.) There was no "nice" algebraic way to solve the final equation involving an angle (which had the variable both inside and outside trigonometry expressions). Two methods are shown: (1) Solving by Newton's Method, and (2) Solving graphically.

### New math puzzle

If the number ABC is written "in decimal form", it means it has value A × 100 + B × 10 + C × 1.

Given that identical letters stand for identical digits, and different letters are different digits, what are A, B and C if the following numbers are written in decimal form and:

ABC + AB + A = 300?

You can leave your responses here.

## 6. Final thought: beliefs

Considering Trump's astonishing announcements that he's appointed Stephen K. Bannon (former manager of the right wing Breitbart News) as a strategist, and that he's going to kill NASA's climate research budget, it's worth contemplating Voltaire's statement:

Those who can make you believe absurdities can make you commit atrocities. [Voltaire, 1694-1778]

Until next time, enjoy whatever you learn.

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