# Activities from the Joint Mathematics Meeting 2004

Phoenix, Arizona
January 2004

The Sketchpad User Group had its first meeting of 2004 at the Joint Meetings of the American Mathematical Society and the Mathematical Association of America in Phoenix. This page collects the activities and sketches that several participants shared with their colleagues at the User Group meeting. You can download these Word files and Sketchpad documents individually, or as a complete collection in a .zip archive or a .sit archive. You are free to use these materials for your personal exploration and for use with your own classes, and to duplicate them for those purposes.

## Computer Activities for College Geometry

Presenters: Bill Fenton, Bellarmine University, and Sr. Barbara Reynolds, Cardinal Stritch University

Presentation Description: We are developing a college geometry textbook based on exploratory activities using Sketchpad. We will demonstrate a sampling of activities from several topics in our book.

Presentation Materials:

## Creating Fractals from Points in GSP

Presenter: Virginia R. Jones, Central Connecticut State Universtiy

Presentation Description: Since GSP4 came out, Ginny has been using it in her Math 409 course. Playing around with it this fall, she discovered that the iteration option on the transform menu allows the user to create standard fractals working from points instead of segments. At higher iterations, the points coalesce to form a "complete appearing" fractal.

Presentation Materials:

## The Conchoid and Trisection of Angles

Presenter: Jim Parks, State University of New York (SUNY), Potsdam

Presentation Description: The conchoid of Nicomedes is an impossible construction with ruler and compass, but it's an easy one on Sketchpad. It can also be used to trisect angles. An illustration of the curve and the trisection of an angle will be given.

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## Tools for Symmetry Investigations

Presenter: Dr. Jim King, University of Washington

Presentation Description: Sketchpad tools can be used to create symmetric wallpaper patterns of the 17 possible types, but also to analyze existing symmetric patterns such as Escher prints by bringing them into Sketchpad. This presentation will show some examples of such tools and symmetry analysis.

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Presenter: Charles E. Oelsner, Manlius Pebble Hill School

Presentation Description: JavaSketchpad Calculus Applets consists of six applets, The Geometer's Sketchpad constructions that generate the applets, online student activities to accompany the applets, and explanations of how the applets were written. The applets illustrate features that are new to JSP4, features available to JSP but not GSP, and work-arounds to accomplish constructions, such as graphs of functions, that are supported by GSP but not directly available in JSP. They can be viewed on Manlius Pebble Hill School website, JavaSketchpad Calculus Applets page.

Presentation Materials: Download all the materials at once (in either a .zip archive or a .sit archive) and open the "open_me.htm" file to get started, or choose from:

• Secant/Tangent:
• Area between Curve and x-axis:
• Inverse Function Theorem:
• Derivative Definitions:
• Area Function:
• Volume of Cone:
• Construction details: an explanation of how the applets were made.

## Triangle and Calculus Activities

Presenter: Melissa Burkhead, St. Andrews Episcopal School

Presentation Description: While Melissa was unable to attend the conference, she contributed several sketches and activities. "Triangles at Work" is adapted from Discovering Geometry, and "More Triangles at Work" extends that activity. "Sierpinski Carpet," "Newton's Method," and "Tangent Polar" are activities she posed to her AP Calculus students.

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## Physics Activities

Presenter: Chuck Caley, Toledo High School

Presentation Description: Chuck was unable to attend the conference, but contributed several sketches he created for his physics students covering refraction and reflection of light, retrograde motion of planets from the Ptolomeic and Copernican views of the solar system, and force diagrams for a stoplight suspended between two poles and a box sitting on a slope.

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