Precalculus Graphs Models and Graphing Calculator Manual Package - 4th Edition Author:Marvin L. Bittinger, Judith A. Beecher, David J. Ellenbogen, Judith A. Penna The authors help students "see the math" through their focus on functions; visual emphasis; side-by-side algebraic and graphical solutions; real-data applications; and examples and exercises. By remaining focused on today's students and their needs, the authors lead students to mathematical understanding and, ultimately, success in class.