The Evolution of the Cartesian Connection
One of NCTM's ten standards for school mathematics is Representation: “Representations [such as diagrams, graphs, and symbols] should be treated as essential elements in supporting students' understanding of mathematical concepts and relationships; in communicating mathematical approaches, arguments, and understandings to one's self and to others; in recognizing connections among related mathematical concepts; and in applying mathematics to realistic problem situations through modeling” (NCTM 2000, p. 67). In my experience, one of the biggest issues students struggle with is the connection between equations and their graphs (referred to as the “Cartesian connection” in an interesting study by Knuth [2000]). Unfortunately, although students are becoming proficient in using algebraic and graphical representations independently, they often do not make the connection between the two representational formats (Knuth 2000; NCTM 2000; Van Dyke and White 2004). In this article, I will explore the history of the graphical representation of functions and curves, specifically, the development of the Cartesian coordinate system as the most common frame for this graphical representation.