In this month's first tip, you will discover that the Table feature is one of the most powerful underutilized tools for graphing functions on a graphing calculator. John Hanna's tip shows you how to use Web plots and gives a nifty program for exploring chaotic behavior in recursively defined functions. In our third feature, John Losse compares two methods of graphing implicitly defined functions: 3D graphing and the “zeros method.” This month's showcased Web site is the Data and Story Library (DASL), housed at Carnegie Mellon University. It is definitely worth a visit!

# Search Results

### Daren Starnes and Paul Gosse

Al Coons kicks off this month's column with an excellent demonstration of how he uses grouping to organize and store data, regression models, and graphs. Our second tip gives a brief introduction to TI InterActive!, the dynamic mathematics software from Texas Instruments. Not surprisingly, we chose to feature the TI InterActive! Web site for this month's installment of “Surfing notes.”

### Daren Starnes and Paul Gosse

We are especially pleased to offer a technology tip for Hewlett-Packard users this month. Colin Croft, a colleague from Australia, shows some potential pitfalls in using the HP—or any other calculator, for that matter—to evaluate limits. Next, coeditor Paul Gosse gives an inside look at Graph Databases (GDBs). If you have not used a GDB before, you might try to do so after you read his suggestions. In our third piece, Bob Ruzich illustrates some nice calculus extensions of the classic “ball bounce with a motion detector” activity. Appropriately enough, our featured Web site this month is Colin Croft's own site for HP calculator users.

### Daren Starnes

### Edited by Paul Gosse

In last month's column, Bob Ruzich described how to analyze velocity data collected from a CBL/CBR ball-bounce experiment using the ΔList feature on the TI-83 graphing calculator. This month, Ruzich returns to share strategies for verifying the law of exponential change using a CBL or CBL 2 voltage experiment. Next, coeditor Paul Gosse gives you a fresh look at teaching linear programming with the TI-83 and spreadsheet software. Be sure to look at some of the fine differences that Paul discusses between “free-cursoring” and tracing. Our “Surfing note” takes you to Japan for a look at some dynamic, interactive Java applets.

### Daren Starnes and Paul Gosse

This month, Maurice Burke kicks off the “Technology Tips” column with a TI-92–enhanced investigation of repeating decimals. In this article, Burke shows how to circumvent the default number of digits stored and displayed by the calculator. Next, Stephanie Kolitsch reveals an error in the sum(seq) command on many of the Texas Instruments calculators. She traces the mistake to an error in the thirteenth or fourteenth decimal place and then shows how to avoid this problem. Bob Ruzich returns with his third piece in the series “The Arithmetic of Calculus.” This time, Ruzich shares a CBL 2/CBL activity that involves voltage and that leads students to a deeper understanding of the average value of a function. Our featured Web site is an interactive, multimedia exhibition showing the uses of mathematics in several career fields.

### Daren Starnes and Paul Gosse

The following CBL 2 laboratory investigation allows students to explore acceleration caused by gravity and to work backward from their acceleration data, using the cumulative sum of a list command, to examine the corresponding velocity and position functions. We can also perform this experiment with a CBL by using the CBL Physics APP or the physics program from Vernier Software.

### Paul Gosse and Karen Flanagan Hollebrands

This month's column sees a return to dynamic geometry. Daniel Scher presents a “proof,” which he claims is rigorous, of why the midpoints of the sides of a quadrilateral, joined in order, produce a parallelogram. Do you agree? Our second tip is a worthwhile introductory activity for any group new to a particular technology. Susan Hvizdos challenges us with a TI-83 Plus Scavenger Hunt.

### Paul Gosse and Karen Flanagan Hollebrands

This month's tip centers on an alternative view of functions. Instead of perpendicular axes for domain and range, we explore parallel axes. This idea has been around for a while (see the references in Bridger and Bridger ([2001] and in the “Surfing Note”), but we hope to breathe new life into this fascinating representation of functions with two easy-to-use programs for the TI-83 Plus. We provide an introduction to mapping diagrams (also called function diagrams) and the code for one program to produce them using the TI-83 Plus. Information about the second program will be given in “Technology Tips” in May. Both programs are available electronically, so users do not have to type the programs into their calculators.