About the Cover

On a clear day, visitors to the top of the Gateway Arch in St. Louis, Missouri, can see up to thirty miles to the east or west. The Arch, towering 630 feet (192 meters) above the banks of the Mississippi River, commemorates the westward expansion of the United States in the 19th century. It takes the shape of a catenary curve, which can be approximated using a quadratic function. You will study quadratic functions in Chapter 5.

About the Graphics
3-D Lissajous curve. Created with Mathematica. A 3-D Lissajous figure is constructed as a tube around a trigonometric space curve. The radius of the tube is made proportional to the distance to the nearest self-intersection. For more information and for programs to construct such graphics, see: www.wolfram.com/r/textbook.