Anders Sanne
Morten Misfeldt

A discussion on a mountain in
Iceland…
• How to increase the use of GeoGebra for producing mathematical text.
– What is the role of GeoGebra in the production of documents?
• Something that you write about
• A good machine to produce illustrations
– What could it be?
• Interactive illustrations
• Answers to mathematical assignments delivered in
GeoGebra

• GeoGebra is strong on different mathematical representations
• Text is the archetypical ”discursive” – or linear
– representation.

Concept
Treatment
Register A Register B conversion
Mathematical activity constist of transformations of semiotic representations
Register: ”space of semiotic representation” (2dplot, algebra, natural language)
Treatment: transformations inside a register
Conversion: transformations that change register but maintain conceptual reference

• The unit circle in different registers x 2 +y 2 =1 ”the unit circle”
• Treatment
• 3x+9=0 => x=-3
• Conversion
• 2x+1 =y can be shown as

Discursive Non discursive
Multifunctional Ex: Natural language monofunctional Ex: algebra
Ex: Geometric figures
Ex: Cartesian graphs

• GeoGebra is strong in its support for non discursive registers
• Less strong with Discursive
– Problem with discursive expansion
• Proofs
• Explanations
• Narrations
• All sorts of reasoning activities

Two approaches to text in GeoGebra
• Embed GeoGebra in word processing.
– Google gadget and save as webpage
• Include text processing and formulas in
GeoGebra
– The improved text box
– A ”caption” or text view?
– Dynamic use of txt

A text view could be here

Producing mathematical documents
• Integrated text view could make it possible to produce simple printable mathematical documents.
• Using only GeoGebra for math assignments and test situations
• Avoid cut and paste
• Strong integration with the other views in
GeoGebra

• With a text view GeoGebra could produce solutions to typical K-12 assignments
– A figure
– Some calculations
– Text describing the problem and solution

Documentation of GeoGebra based reasoning
• Arguing for reasoning strategies and procedures
• Describing observations
• A complement to the construction protocol
(there is a caption field in the new construction protocol)
• Enhancing (mathematical) literacy

• Writing should of course be considered when
using GeoGebra for teaching mathematics
• This can be done by embedding GeoGebra applets in a text domain
• But creating a simple text view could supplement this approach