# Function Diagrams update

#### Presentations at Asilomar

I will be speaking about function diagrams at the December 7 meeting of the California Math Council (North) in Asilomar. I hope to see some of you there!

I first learned about function diagrams at Asilomar, many years ago, from Martin Flashman, a professor at Humboldt State University. Strange coincidence: Martin is also going to speak at Asilomar this year, about the same topic! I hope we’re not scheduled for the same time , because I’d like to attend his talk.

If you don’t know about function diagrams, read all about them on my Web site, and/or in my previous posts on this blog. They are a little-known but powerful educational tool which can be used profitably all the way from middle school math to calculus.

#### New GeoGebra file

I added a file to my GeoGebra function diagrams packet on my Web site. It is called name-that-fd. It includes nine diagrams for mystery functions in one file. You choose one of the functions by using a slider. The intended use is to show students a diagram, and have them guess the function. You can animate the diagram, or move the x along its axis manually. x and y values are shown on the side. The activity is a good way to gauge and reinforce understanding of the functions, and usually triggers excellent conversations. The functions I included are appropriate late in an Algebra 2 class, in Precalculus, or early in Calculus.

The same activity, more or less, can be done by using the Cabri Java applets on my site. (When time opens up, I will replace them with an HTML 5 version, as Java triggers scary messages.) Instead or in addition, you can use a paper version of the activity (Get two versions as PDFs here.)

What’s nice about the new GeoGebra version (which can be downloaded here) is that you can change the functions if you want, by editing the list called “images”. This is easily done if you know a bit about GeoGebra. (If not, get in touch, and I’m happy to help you.)

–Henri

More on function diagrams here.