While the first handheld calculators performed basic mathematical functions – adding, subtracting, division – the first graphing calculator wasn’t introduced until 1985.
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Additional features included executing tasks with variables, plotting graphs, and solving equations simultaneously.
Plus, graphing calculators typically allow users to create programs for scientific or educational applications.
Finally, because of the amount of information needing to be displayed, screens of graphing calculators are bigger than their more traditional counterparts.
In 1993, Texas Instruments released the TI-82, an upgraded version of the TI-81. It was an immediate hit with users and was the de facto standard in classrooms and laboratories across the United States for the next ten years.
Even though it was replaced in 2004 by the TI-83, the TI-82 is a workhorse still easily available on Ebay and commonly used by students in high school and college.
Have a TI-82 you’d like to use? Want to know if its features will work for your purposes? We’ll cover all the relevant details below.
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The TI-82 comes with a 6 MHz Zilog Z80 processor and 28 kB of RAM.
The monochrome display screen is 96 by 64 pixels and has up to 8 lines of text with 16 characters each.
It’s powered by four AAA batteries and an additional lithium battery to preserve stored data when the primary batteries are being changed.
The TI BASIC programming language is also included, and there’s an i/o port to connect to other devices.
Almost all buttons have two functions, and some have three. The primary function is printed on the button.
Secondary functions are printed in blue or gray above the button and are accessible after first pressing the 2nd key.
Tertiary functions, if available, are listed in white above and to the right of the button and are accessible after first pressing the ALPHA key.
Depending on exactly which version of the TI-82 you have, there will be some design variations.
After being introduced in 1993, the first redesign took place in 1999 when the original sloped screen was reconfigured, and the body of the calculator was made more contoured.
A second redesign in 2001 produced yet another slightly different case style, improved screen quality, and internal circuit board changes which reduced production costs.
The TI-82 can be a bit daunting at first, especially as multiple functions are tied to one key or button. Here’s an overview of the basics you’ll need to know to get started.
- Turn on and off: To turn your TI-82 on, just press the ON button. To turn it off, however, you’ll need to first press the 2nd button and then ON, as OFF is the secondary function of the ON button.
- Adjust screen brightness: To make the screen brighter, press the 2nd key and then press down on the DOWN arrow until the brightness is where you want it. To make the screen darker, press the 2nd key and then the UP arrow until it’s as dark as you want it.
- Clear screen: Press the CLEAR button.
- Change screens: Press 2nd and QUIT. This may also move you to another screen if the current one does not allow data to be entered.
- Change characters: Replace a cursor-position character by pressing the new character you want to use. Insert a character at the cursor position by pressing the 2nd key, then the INS button, and then the new character you want to use. Press DEL to delete a character at the cursor position.
- Change MODE (use split screen, display numbers as power of ten, or change radians to degrees): Press the MODE button, use arrows to move to a new mode, and press ENTER to select the new mode. Return to the home screen by either pressing CLEAR or 2nd and QUIT.
- Perform numeric calculations: On the display screen, the division sign will be / and multiplication sign will be *. Subtract using the – key and (-) for negative numbers. Parentheses are used to indicate order of operations. Use the ^ button to enter an exponent.
- Find the root of a number: Enter the root index number, press the MATH key, press 5 to insert an indeterminate root symbol, then enter the number you need to find the root of. There is a shortcut for square roots only. These may be calculated by pressing the 2nd key, then the square root key, the number whose square root you want, and ENTER. Cube roots can be found by pressing MATH, selecting item 4 by entering 4, and then entering the number you need the cube root for.
- Raise a number to a power: Enter the number you need raised followed by the ^ button. Now, enter the power number and press ENTER. To raise a number to the second power, just enter the number followed by pressing the x squared key. For the third power, enter the number, press MATH, then 3 to select item 3, and ENTER.
- Perform operations with fractions: The division symbol ÷ will go between the denominator and the numerator. For example, ½ would be keyed in as 1÷2. Make sure to use the correct operators between fractions. When you press ENTER, the default result will be in decimal format. To display the result as a fraction, press MATH and choose Frac. Then, press ENTER.
TI-82 Specialized Functions
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Once you’re familiar with the basics of using your TI-82, you’ll be ready to move on to its more specialized features discussed below and which give the calculator its real power.
For the nuts and bolts info on how to perform these operations, however, you should refer to the official TI-82 Graphing Calculator Guidebook.
Graphing & Evaluating
- Graphing a function is as easy as pressing the Y= button and then entering the variable x. Select the ZOOM key for a standard-size window or select the Window key and use the arrow buttons to choose a custom size. You can also evaluate functions without having to go to the Graph screen.
- In addition, you can easily erase or change a function, trace a function, and find the maximum and minimum points on a graph. The TI-82 allows you to find the value of a function for a given x value and to find the intersection point of two graphs.
- Calculus functions include determining the numerical derivative of a function, using points on a graph to determine the value of a derivative, and drawing a tangent line at a specific point. There are also multiple ways to find the value of a definite integral.
- It’s also easy to enter and store multiple, custom-size matrices to be used in later operations such as multiplying matrices or using Gauss-Jordan Elimination or Gaussian Elimination. Unfortunately, unlike the TI-82 Plus or the TI-84, the TI-82 does not have re and rref functions.
Additional special functions include the ability to change from degree mode to radian measure, graphing functions on an interval, and graphing trigonometry functions.
You can also use the LOGIC features to include operators like “and,” “not,” and others to create truth tables or even Boolean algebra.
In addition, you can find the terms of sequences, recursion formulas, and the arithmetic of lists.
Programming on the TI-82
Of course, beyond being a graphic calculator, another powerful feature of the TI-82 is it comes with the TI BASIC programming language.
This allows users to write programs to perform ongoing tasks and calculations instead of being forced to do each one individually.
First, you’ll access the program editor by pressing PRGM. Then, select NEW on the menu and press ENTER. After that, you’ll be prompted to name your new program.
From there, you’ll go to the program editor where you can key in your program using commands available by pressing the PRGM key.
Once you’re done, you can access all your saved programs from the home screen by pressing PRGM, then EDIT, and then selecting the program you want to run.
Check out this tutorial to learn how to create a simple program using most of the commands available in TI BASIC.
The TI-82 is a much-loved calculator, and there is plenty of information available to help you navigate its use.
For example, this overview of its specifications and additional resources is a good place to start. Another useful site is TI-Freakware which is devoted to all things Texas Instruments.
Finally, there are many instructional videos available on YouTube:
Despite being discontinued by Texas Instruments in 2004, the TI-82 is more than just a collector’s item. Instead, its power and versatility—and low price on Ebay—make it an excellent starter calculator for math students.
Plus, once you’re thoroughly familiar with its operation, you’ll be ready to move up to a calculator with even more bells and whistles if the need arises.
Want to learn more about graphing inequalities with a calculator? Check out our guide to the best resources available to do this!