Dynamic Geometry in Graphing Calculator

The dynamic geometry system is a typical CAI application that utilizes computer technology to guide geometry learning. In our research of the dynamic geometry on handheld devices, we have successfully implemented a brand new system called "mathematic sketchpad", a part of the Noah graphing calculator. Compared to other similar products like TI or CASIO graphing calculator, the sketchpad owns features such as advanced mathematic functions, true color screen and touch-pen operations that emphasize powerful and user-friendly purpose. Different from PC software, the sketchpad have advantages such as portability, mobile teaching and classroom interactive teaching that are good for mathematics education. Besides, the dynamic geometry system on "mathematic sketchpad" is built on computer algebra basis that allows numeric-symbolic combination to handle even difficult tasks. In this paper, we will briefly introduce the implementation of sketchpad, corresponding theories that make dynamic geometry possible, and give some examples that can be used in teaching.