摘要:Purpose: This study aimed to reveal the relationship between elementary school mathematics teacher candidates' determination levels of image sets of functions in R2 and R3.Design/Methodology/Approach: This study was conducted with 49 elementary mathematics teacher candidates and the correlation design from quantitative approaches was used. For the given purpose, the data were collected by 2D and 3D tests. The 2D test was used to reveal the students' level of determining the image sets of the functions in R2 and the 3D test was used to reveal that in R3. In the data collection process, the graphics of the questions in 2D and 3D tests drawn with the support of GeoGebra were presented to the students together with the tests. Correlation analysis was used to compare the levels of students in determining image sets of functions in R2 and R3.Findings: According to findings, it was found that there was a high level, positive, and significant relationship between the students' levels of determining the image sets of the functions in R2 and R3. Another conclusion about the study was that the students were more successful in determining the image sets of functions in R3 than in R2. This is thought to be a result of the dynamic feature of the GeoGebra software.Highlights: It was observed that the GeoGebra program was important in determining the image set of a function, especially in R3. For this reason it is thought that using activities designed with the GeoGebra program in related lessons can be effective in teaching two-variable functions.