There's a story behind every piece of software, but I doubt any can compare with the tale of Graphing Calculator, which shipped with the first PowerPC-based Macs and continued to be bundled with Mac OS 8 and, in version 1.3, with Mac OS 9. I won't attempt a second-hand retelling, since Ron Avitzur, Graphing Calculator's primary developer, has done such a good job already, but suffice to say, Graphing Calculator was a program written by Ron and another developer, Greg Robbins (who lived a few miles from us in Seattle when we were there) after their jobs at Apple had ended - the twist is that they continued to go into work at Apple every day, using their still-active badges and offices. Graphing Calculator's genesis is probably the ultimate skunkworks story - there was nothing official about it until the very end, and yet it shipped on 20 million Macs and helped untold numbers of students better understand mathematics.
Now a new chapter in Graphing Calculator's story has begun. Ron has just released a Mac OS X version of Graphing Calculator 3.5 through his company, Pacific Tech, which sold more-advanced versions of the program even while Apple bundled the free version. Interestingly, most of the porting work was done by Marco Piovanelli, a programmer who's best known as the creator of the WASTE text engine used by innumerable Macintosh programs as well as Graphing Calculator itself.
My math background is sufficiently weak and distant that I cannot evaluate the program on its mathematical merits, but a glance at the feature list reveals an impressive set, given that it can graph simple and complex equations in two, three, and four dimensions, including multiple equations on the same graph. You can even have Graphing Calculator automatically substitute a range of values for a parameter in an equation and animate the resulting graph as the numbers change. A slew of examples and demos show off just what the program can do, and you can see some screenshots of some seriously high-end mathematical features at the Complex Functions page below. As Ron jokingly told me, "It helps visualize functions of a complex variable in four dimensions, a feature every seventh grader needs!"
You can save any equation in Graphing Calculator's own format, of course, but you can also save in RTF (the equations and graphs are saved as graphics) for importing into other programs, in HTML format for posting on the Web, and in QuickTime movie format for showing off animated equations. It's also easy to change the look of the graphs, add text boxes with explanations, and print your equations. There's also a free Graphing Calculator Viewer program that lets you view and interact with (but not type into) Graphing Calculator documents, making it a useful demo version.
Previous versions of the program have long been popular with math teachers around the world thanks to the ease with which it enables students to visualize highly abstract mathematical concepts. An included (look in the Help menu) activity book called Learning Math with Graphing Calculator helps you explore how you can learn more about mathematics using the program.
If you're at all interested in math, or if you help others learn math, take a look at this new version of Graphing Calculator for Mac OS X. You can download a free version of the limited Graphing Calculator 1.3 for Mac OS 9 or 1.4 for Mac OS X to check it out. If you want the full feature set, Graphing Calculator 3.5 for Mac OS X 10.3.6 or later costs $60 for students, teachers, and parents, $40 for students with ID using it on only a single machine, or $100 for everyone else. Mac OS 9 and Windows versions are also available for the same prices.