This paper presents a conceptual analysis for students' images of graphs and their extension to graphs of two-variable functions. We use the conceptual analysis, based on quantitative and ...

Microsoft Excel can perform numerous statistical functions, as well as create charts from statistical data. Statistical data includes numeric variables or word variables, also called categorical ...

Functions of two variables can be visualized in many ways: heat maps in 2D, contour curves in 2D, wireframes in 3D, surfaces in 3D. We begin by defining a function of two variables, building an array ...

https://doi.org/10.4169/college.math.j.45.1.054 https://www.jstor.org/stable/10.4169/college.math.j.45.1.054 Summary We present a result of Rosenthal, which shows ...