ABSTRACT
This chapter is about graphics that logically exist in two dimensions. The next chapter is about graphics that logically exist in three dimensions, even though in practice they must be projected into two dimensions. Two-dimensional graphics arise as representations, called graphs, of real-valued functions of a single real variable, and being able to plot such graphs easily is crucially important in many mathematical investigations, in which the underlying data being plotted may be either algebraic or numeric. But two-dimensional graphics also arise from problems in two-dimensional geometry, which can be much easier to understand visually than in the abstract. These two aspects of graphics merge to some extent in algebraic or coordinate geometry.
