David E. Bock & Franklin Demana 
Precalculus: Graphical, Numerical, Algebraic, Global Edition [PDF ebook] 

For courses in Precalculus The Rule of Four: A Balanced Approach Precalculus: Graphical, Numerical, Algebraic provides a balanced approach to problem solving and a consistent transition from Precalculus to Calculus. A principal feature of this text is the balance among the algebraic, numerical, graphical, and verbal methods of representing problems: the rule of 4. This approach reinforces the idea that to understand a problem fully, students need to understand it algebraically as well as graphically and numerically. The 10th Edition introduces graphing technology as an essential tool for mathematical discovery and effective problem solving. This edition also features a full chapter on Statistics to help students see that statistical analysis is an investigative process.