Experiences of undergraduate students with literal symbols

摘要

The study investigated the results of an experiment where the researcher observed misuses of literal symbols by university students when they had to solve integration exercises. 150 university students were selected as the sample of the study. The study used examination papers, semi-structured interviews and in-class observations as the data collection instrument. The study showed cases of difficulties experienced by students when they had to use letters like x, y, u, v, ... to solve the exercises. The main conclusion is that students have letter x as their prototypical concept image of literals used in algebra or calculus and, for this reason, they have difficulties in using other letters. The study presented several classifications of students' answers showing wrong uses of literals, and some examples of student' answers, in some cases followed by fragments of interviews where a researcher asks the students for the reasons of their use of literals, in other cases without any explanation.