The manual that ships with the TI-89 is a killer, presenting over 500 pages of clear, concise definitions, function explanations, examples, drawings, and appendices. It's divided into well-organized chapters that cover all the major features of the calculator. Graphing functions include basic function graphing, parametric graphing, polar graphing, sequence graphing, 3-D graphing, and differential-equation graphing. Additionally, the TI-89 includes symbolic manipulation, constants and measurement units, statistics and data plots, a numeric solver, a text editor, programming capabilities, tables, a split-screen function, variable management, and the ability to link to other calculators or a computer.

The large, color-coded keys are easy to read and find--a nice touch on such a feature-heavy calculator. An improvement over earlier Texas Instruments graphing calculators is the addition of one-touch X, Y, and Z variable keys. The large LCD screen is also adjustable to your environment; we were able to view it clearly in a variety of lighting. The TI-89 comes with an attached, hard slide cover that protects it from getting knocked around in a backpack.

The TI-89's flash technology allows you to upgrade to future software versions so you don't have to continually invest in new calculators. The whopping 500 K of memory is more than sufficient for your stored functions, programs, and data. You can also create custom menus or use the default menu. Another cool feature is the Program Editor, which gives you the ability to program. The TI-89 also comes with an input/output port and cable, letting you synch up with other TI-89s or TI-92s. --Jill Lightner

Pros:

• Large keys
• Easy-to-read LCD
• Includes input/output port and cable
• Allowed in AP, SAT, PSAT/NMSQT tests
• Comprehensive, illustrated manual

Cons:

• None

Built-in advanced mathematics software includes a Computer Algebra System (CAS) enabling you to manipulate mathematical expressions and functions (factor, solve, differentiate, integrate, and more). It also includes differential equations, 2-D graphing and data analysis, 3-D graphing with rotations, linear algebra, interactive numeric solver, constants, unit conversions, statistical regressions, and optional assembly language programming.

Product Description
MODEL- TI89GRAPHICS DESC.-TEXAS INSTRUMENTS GRAPHING CALCULATOR FEATURES- * Electronic upgradability of software including maintenance and feature upgrades. * Advanced Mathematics Software functionality suitable for college mathematics and engineering coursework. * Symbolic manipulation for algebra and calculus. * Pretty Print shows equations and results with radical notation, stacked fractions, and superscript exponents. * Real and complex results. * Active home history screen can hold up to 99 previous equations for deep recall. * About 180K bytes of user-available RAM (memory). * 384K bytes of user-available Flash memory in the form of user data archive. * Graphs functions, parametric equations, polar equations, recursively -defined sequences, 3-dimensional surfaces, and differential equations. * Shows numeric evaluation of functions in table format. * Slope and direction fields for exploring differential equations. * Interactive analysis of function values, roots, maximums, minimums, integrals, derivatives, intersections, inflection points, and arc lengths. * Exact symbolic solutions to many 1st- and 2nd- order ordinary