# IntMath Newsletter: radius of curvature, log curve, free math videos

By Murray Bourne, 23 Jul 2010

22 Jul 2010

In this Newsletter:

1. Math of the great summer brain drain

2. Math tip: Radius of Curvature, an application of differentiation

3. Slope of the logarithm curve at any point

4. Friday math movie - Khan's Academy

5. How to import GeoGebra files into JSXGraph

6. Final thought – stay positive

## 1. Math of the great summer brain drain

Here is some interesting information about how **forgetting** works, and what we can do to reduce it.

Do you want to be a successful math student? This could be a good place to start.

**Suitable for: **Everyone.

Everyone knows students drop a few grades in their knowledge during the summer months. What's the math behind this? Read more: Math of the great summer brain drain |

## 2. Math tip: Radius of Curvature, an application of differentiation

I re-wrote a page on Interactive Mathematics recently and thought you may find it useful.

A reader sent in a question asking how to find the radius of curvature if we don't know the function. I solve this problem in 3 different ways. You can get some good mathematical understanding from this.

**Suitable for: **Everyone. Even if you have never heard of calculus yet, you will come across it one day and this example gives you an idea about what it can be used for.

#### Summary of the page:

- What is radius of curvature and why study it?
- Example of radius of curvature involving a cubic curve
- Exploration of radius of curvature using an interactive graph
- A second example (the one sent in by a reader) that is solved in 3 different ways:
- Using a
**parabola**to model the data and differentiation - Using
**linear approximations**and concepts of calculus - Using the formula for the
**circle passing through 3 points**

- Using a

In this example, we learn about radius of curvature and one of its applications. Read more: Radius of Curvature |

## 3. Slope of the logarithm curve at any point

**Suitable for: **Everyone. Once again, this example involves differentiation (a calculus topic), but the main concept is easy for everyone to understand: as you move around a curve, the slope changes.

This is a new interactive graph in IntMath. You can drag a point around a logarithm curve to learn about the changing slope. You'll laso learn what a log curve looks like. Learn more: Slope of the Logarithm Function |

## 4. Friday math movie - Khan's Academy

**Suitable for: **Everyone.

Here's a wide range of free videos by a guy that clearly loves to teach. This is a very popular math video series. Watch a typical video. This one is about the Unit Circle: |

## 5. How to import GeoGebra files into JSXGraph

**Suitable for: **Math computer geeks.

This article explains how you can create interactive math applets using GeoGebra (which is easy) and import those files into JSXGraph (which displays the math in a browser, and is cross-platform and cross-browser). Read more: How to import GeoGebra files into JSXGraph |

## 6. Final thought – stay positive

A lot has been written about the power of positive thinking. But it's true!

The people who have a negative approach to math ("This is dumb!" "This is never used in the real world!") and do nothing much to improve their skills, get into a cycle where they get worse.

Here's a thought from self-help speaker and author Brian Tracy:

"The more positive you are when you think and work toward your goals, the faster you achieve them." [Brian Tracy]

Until next time, enjoy whatever you learn.

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