The learning of logarithmic functions by 12th-grade students based on modelling tasks

The relevance that the application of what is learned in Mathematics to everyday situations has in student learning has led us to develop an experiment on teaching the logarithmic function using modelling tasks. Based on this experiment, we intend to characterize the activities of 12th-grade students in the performance of modelling tasks concerning topics of logarithmic functions and identify the difficulties they may present while solving these tasks using a graphing calculator. When adopting a qualitative and interpretative approach, data were collected through students' written records while solving the proposed tasks using the graphing calculator. The results indicate that the students show that the modelling tasks promoted group work and their interest and participation in class. During the exploration of the tasks, students performed activities that result from the accomplishment of modelling phases such as understanding the statement of the task, organizing and analyzing data, building and validating the model that best fits the data, and exploring the model, either in the introduction of the logarithmic function and its derivative or in the consolidation of the acquired knowledge. In such activities, some students presented difficulties regarding the properties and characteristics of the logarithmic function and its graphic and symbolic representation. The phases of the modelling cycle also made it difficult for students to use the graphing calculator, namely in performing statistical regressions and setting the visualization window.