VINTAGE Texas Instruments TI-85 Graphing Calculator (1992) NEW IN FACTORY PACKAGING The TI-85 graphing calculator was made by Texas Instruments based on the Zilog Z80 microprocessor. It was designed in 1992 as TI's second graphing calculator, replacing the TI-81. Please Note: Packaging is sealed, but the plastic packaging is cracked or broken in areas due to age (see photos). Product Details - Designed with students of higher math in mind, the TI-85 is a scientific calculator that offers a wealth of features and functions that will take you smoothly from pre-algebra all the way through college calculus. Its data I/O port and unit-to-unit link (compatible with all TI-85 and TI-86 models) allow you to easily transfer your final graphs and equations among systems, while the 28K RAM and customizable menu keys provide quick access to necessary programming functions. As you advance through classes, simply reprogram the keys to keep up with your new textbook chapters. Functions are widely varied, and include the ability to solve for systems-of-equations, polynomial-root, or any variable in an equation. Graphing possibilities include parametric equations, polar equations, and solutions to differential equations. Statistical analysis runs the gamut from linear, logarithmic, exponential and power to quadratic polynomial, cubic polynomial, and quartic polynomial regressions. In addition, data is viewable as strings, pictures, or vectors. Simultaneous separate graph capability and 15 interactive zoom features are also included. The display is a generous eight lines long and 21 characters wide; this unit is powered by four AAA batteries, with a dependable long-life lithium ion providing memory backup.