Finding Points of Intersection with The Geometer's Sketchpad

So Frank asked me about finding intersections of plotted linear functions at our Web 2.0 session last week. It turns out that constructing the intersection of two lines is trivial but of two function plots is not.

I told him the story about how happy I was to have written a custom tool to take two linear functions as input and create their point of intersection for Stephanie. The .gsp file is here.

At least, I was happy until I asked my pal Shawn Godin about it and he very quickly created a sketch that takes two polynomial functions (and maybe other kinds), and the origin and plots the functions, creates a locus of all the points of intersection found using Newton's Method, and labels one of them. You can then drag the point on the locus through all the points of intersection. His .gsp file is here.

Guess which one of us is working on our PhD in Mathematics?

Thanks Shawn for giving me permission to share the sketch. I'll be curious to see if this post gets as much traffic as the post about graphing inequations in Sketchpad, which also reported Shawn's guru status in the Sketchpad community.

Added an Equation Editor to my Blog

If you scroll to the very bottom of the page you should see an equation editor that I found via the Charlotte Area Math Teacher's Wiki (recommended by Vic in the comments to the previous post).

You can generate mathematical text visually or using Latex and save the resulting image as a .png. The Latex code is also useful in various other equation editors or for embedding mathematical text in blogs or wikis.

How cool is that!

Math on a SMART, I mean Interactive White, Board

In a shout out to someone he calls the Northern Mathman, Geoff Day drew my attention to this incredible Java application for doing mathematics that is particularly well-suited to an IWB or tablet. Although it doesn't work quite as well for me as it does in this introductory video, with a little practice it could change the way I think about equations and mathematical calculations.

You can download it or use it directly on the web.