Black Dots: Newton's Method and a Simple One-Dimensional Fractal
Students in a standard calculus course learn Newton's method for finding the root of a differentiable function. Although they may often see a diagram that visually demonstrates how this method works, it often soon becomes yet another algorithm to memorize or to program into a calculator. In addition, students are sometimes told that using Newton's method on simple complex-valued functions can lead to beautiful fractal patterns. However, the connection between the sequence of steps that they have learned and the corresponding fractal images is fuzzy at best. This article describes a calculator exercise that can help students develop a better visual and numeric feel for Newton's method and discover how Newton's method can lead to a simple, one-dimensional fractal.