Exploring didactic difficulties and complementary measures according to the definition of definite integral as the area in the 2022-revised curriculum

This study aims to analyze the expected didactic difficulties and prepare complementary measures for the concept of definite integral, defined as 'the area between the curve and the -axis' in the 2022 Curriculum, following the 2015 Curriculum. To this end, the development of the area concept was examined by comparing the 2022 and 2015 Curricula and analysing textbooks. The analysis revealed difficulties in understanding definite integral as the area due to the limited development of the area concept, such as only justifying the method for calculating the area of a rectangle when the sides are natural numbers. Additionally, it was found that the situation material for questioning that had already been developed in the 2015 Curriculum, introducing the 'relationship between definite integral and sum of series', were ineffective in the 2022 Curriculum. The material were revised and supplemented for use in the 2022 <CalculusII>. Based on this discussion, improvement measures for the area concept development in the 2022 Curriculum were proposed.