Section 1Visual Calculus / Pre-Calculus
An excellent site that has tutorials covering virtually everything about functions. It also has interactive online applets, practice problems with solutions, examples, quizzes, and tutorials on using graphing calculators.
Section 1-1: Four ways to represent a functionQuickMath
This site uses Mathematica to solve, simplify, expand, or factor equations, systems of equations, and inequalities. It also performs operations with matrices and plots graphs.
Section 1-2: Mathematical Models A Context for Calculus
An excellent site that walks you through the process of generating a mathematical model for the spread of disease. Includes exercises and sample models of several diseases.
Section 1.3: New Functions from Old FunctionsComposite functions
This is a thorough explanation of the concept of composite functions and their domains, along with a couple of worked out examples.
Section 1.4: Graphing Calculators and ComputersTexas Instruments
The official site of the maker of widely-used graphing calculators. Ticalc.org
This is the self-described "official" unofficial headquarters for TI graphing calculators. A multitude of programs for a wide range of Texas Instruments calculators can be found here for download. CASIO: Support Classroom With Technology
Casio's official site for their line of calculators, including product information, a program library, and much more. Hewlett Packard Calculators
Hewlett Packard's official site for their calculators, including product information, technical support, and resources for creating and downloading calculator programs.