Development and implementation of RME-based lessons on sinusoidal functions using geogebra

• Main Author: Rellosa, Maria Celeste R.
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Trigonometry; Mathematics—Study and teaching; Mathematics
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/5164
• Institution: De La Salle University

This action research was designed to develop a lesson on sinusoidal functions (sine and cosine) under Realistic Mathematics Education approach. The instructional approach used was anchored to the connection and relationship of three different contexts in trigonometry namely the triangle trigonometry, the circle trigonometry and trigonometric function with their representations using Geogebra. Moreover, the study sought to address the challenges and pedagogical issues in trigonometry by adapting the RME theory for instruction in the Philippines setting. The instructional lesson materials underwent a validation from the four experts and were implemented in a regular heterogeneous class in a private school in Makati not handled by the researcher. It was employed to six pair participants with each pair comprising of two individuals with different abilities along the three-week implementation of the nine lessons of the materials. Qualitative data sources taken from the worksheets, home works, exercises, reflection sheets and field notes observation in every lesson were described, interpreted and compared to arrive at a set of valid findings in determining the support provided by the lesson materials during instruction in the students learning on sinusoidal functions. The interview tasks and test that were collected after the instruction were also incorporated in the results. The following themes came out in determining the support provided by the lesson materials that exhibited in the students outputs in learning sine and cosine function: (1) Relevance of the context in exposing mathematical ideas (2) Bridging the abstract concept of math through visualizations(drawings, pictures, illustrations) (3) Adaptability - this pertains to the students reception of the use of technology in the classroom and students treatment to the new approach--RME based lessons vs. their orientation to traditional classroom and (4) Collaboration. Implications were drawn on providing a similar approach that should have done already prior to conducting the lesson materials offered by this study. This approach would require students in citing observations, comparing, recognizing a relationship and making conclusion as favored by guided reinvention principle of RME. A closer look into the scaffoldings necessary for students to establish a strong connection from right triangle to unit circle and unit circle to graph of sinusoidal functions is suggested.