Abstract:

Slope of a line is defined in mathematics of secondary education and is considered a prerequisite for the understanding of concepts of calculus usually under the notion of rate of change. Students have an image of slope from everyday language as a measure of steepness before entering an algebra course. Moreover, slope is used in other fields besides mathematics, as sciences and economics. In school mathematics, slope is taught in algebra in relation to a line, in geometry as the tangent of an angle, and in calculus related to the derivative. It can be conceptualized as a ratio describing steepness and as a rate of quantities that vary. As a result, students meet different aspects of slope and it is not obvious that they connect them and form a robust overall image of the concept. In the current study, educational material by use of Geogebra was designed, as a way to enhance students’ conceptualization of slope and help them construct the interrelations among its various representations. A Geogebra book has been developed based on the conceptualizations of slope reported in mathematics education research.

Keywords:

Slope, rate of change, Geogebra.