Texas Instruments first came out with the TI-92--also a graphing calculator. However, the calculator had a QWERTY keyboard. A QWERTY keyboard is the layout of a standard computer keyboard. Some standardized tests, such as the ACT, disallowed its use. Texas Instruments then came out with the TI-89--a calculator with similar functions but a smaller, non-QWERTY keyboard. The latest addition to the series is the TI-89 Titanium.
Arithmetic is the study of numbers. Early calculators could perform mathematical calculations with great ease. Algebra involves the manipulation of symbols. There arose a need for a calculator that could manipulate algebraic expressions. The TI-89 comes loaded with CAS--the Computer Algebra system. This is a software program for symbolic manipulation and allows the calculator to manipulate mathematical expressions in symbolic language. The TI-89 calculators are not limited to numeric answers; they can solve equations in terms of variables.
The TI-89 has a 160 x 100 pixel, LCD display screen. This allows graphical display. It also allows you to see the various steps of your calculation, so you can check and correct your work as you proceed. It has a split screen mode, so you can look at a graph and the home screen at the same time.
The calculator is user-programmable. For example, you can write a small program to perform a calculation you would often need. Then, instead of entering the numerous steps each time, you would just call up the program you had written, and provide it with the appropriate data. The language used is TI Basic. You can also create programs in the C programming language or in Motorola 68000 machine language on your computer, translate the programs into TI Basic, then transfer them to the calculator.
The TI-89 has an input/output port and cable. An input/output port is a slot located on the outside of the device that allows for an input or output device to be connected. You can, for example, connect the TI-89 to other calculators. Its flash ROM (read only memory) allows for easy updates.