Texas Instruments TI-85 and TI-86 scientific calculators

The TI-85 and TI-86 calculators appear to be the same for all features described here. Please note that does not mean they operate the same way for all features.

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The calculator.

  TI-85 & 86
Brand name Texas Instruments
Model number TI-85; TI-86

Picture of TI-86 keyboard. (Provided by the author of this page.)

Logic system. Does your calculator use algebraic or RPN (reverse Polish notation) logic? How do you tell? Typically, an algebraic calculator has an = key, used to find a result; an RPN calculator has an ENTER key, used for an initial entry. To add two numbers (say, 2 & 3) on an algebraic calculator, you type the keys "2 + 3 =". On an RPN calculator, you type "2 ENTER 3 +". The sequence is what matters, not the key name; some algebraic calculators (especially the more complex, graphics calculators) use ENTER instead of =.
  TI-85 & 86
Algebraic or RPN? Algebraic. TI graphics calculators have an ENTER key, but use it like an ordinary = key, to complete a calculation.
Algebraic calculators can be subdivided into AOS and DAL. If you know which type yours is, you can write that here. If not, you will figure that out later on the form. DAL

Shift keys. Shift keys are used to get the second (or third) function for a particular key. If there are two shift keys, list both.
  TI-85 & 86
What is the label on the "shift" key(s) yellow-shift: 2nd
blue-shift: alpha (to access the "blue" function of the keys, mainly the alphabet)
Where is the shift key? both: upper left

Scientific notation; entering. Identify the key used to enter the exponent. (It is usually EE or EXP, or similar.)
* A special case concerns entering a number that starts with 1x in scientific notation: do you need to enter the 1? Try it... Calculate 1x1012 * 2. Do it twice, once with the first 1 and once without it. Do you need to enter the 1 to get the correct answer, 2x1012?
* The key for making an exponent negative is the same key used for entering negative numbers.

  TI-85 & 86
What is the label on the key for entering exponents? EE (2nd comma)
Where is that key? middle, above 7
When entering a number that starts with 1x in scientific notation, do you need to enter the 1? (e.g., 1x1012) no
What is the key for making an exponent negative? (-)
Where is that key? bottom row, next to decimal point

Scientific notation; display.

  TI-85 & 86
Most scientific calculators allow you to "force" the display to use (or to not use) scientific notation.

Many calculators allow you to set the number of decimal places displayed.

(Some calculators also have an option for "Engineering notation", which is a variation of Scientific notation. Not important for most people.)
Press 2nd MODE (MODE is the 2nd function of the MORE key). Scroll through the menus with the up/down arrows to select each group of options. Use left/right arrows to select the option; press ENTER to accept each option.
Choose type of numeric display: Normal, Sci, or Eng (first menu).
Choose number of decimal places to display: Float (= no fixed number) or a specific value (second menu).
When done choosing options, press 2nd QUIT (QUIT is the 2nd function of the EXIT key).

Logarithms (and anti-logs). In intro chem we most often use base 10 logs (log10), for example with pH. The log10 is the power of 10 of the number. For example, the log10 of 1000 is 3; and then the antilog10 of 3 is 1000.
* On some calculators, you press the LOG key before the number, and on some you press the number then the LOG key.

  TI-85 & 86
How is the log10 key labeled? LOG
How is the base 10 antilog key labeled? 10x. It is 2nd-shift LOG.
To take the log10 of 1000 which do you enter first, the number or the LOG key? LOG. That is, enter LOG 1000.
The preceding step serves to distinguish AOS and DAL calculators. If your calculator uses algebraic notation, and if you enter the number first, then it is AOS; if you enter the LOG first, it is DAL. The same pattern holds for other one-key functions, such as antilog and square root.

Base e logs (loge or ln) are called natural logs. We do not use these in intro chem, but you are likely to use them if you go much beyond that.
How are the keys labeled for natural logs and antilogs? LN

anti-log: ex. It is 2nd-shift LN.

Miscellaneous. These are functions we do not use in intro chem, but which you are likely to use in other math and science courses. Briefly noted here.

  TI-85 & 86
Angles: degrees or radians

(Some calculators also have an option for "grad". The grad is 0.9 degree, so that a right angle is 100 grad. Not commonly used.)
Press 2nd MODE (MODE is the 2nd function of the MORE key). Scroll through the menus with the up/down arrows to select each group of options. Then use right/left arrows to select the options. Choose Radian or Degree. (There is no function to convert from one to another.)
Press ENTER to actually select the option.
When done choosing options, press 2nd QUIT (QUIT is the 2nd function of the EXIT key).
Polar vs rectangular coordinates 2nd MODE. Scroll down to 4th row. RectC is highlighted as default. If you want polar coordinates, choose PolarC, then also choose Pol from the next row of options. ENTER, and finally 2nd QUIT. (There is no function to convert from one system to the other.)

You. Please provide your name and e-mail, so I can check back with you if there are questions (and maybe have you proofread the web page for your calculator). We will not list your name at the web site without your explicit permission. We will not make your e-mail available in any case.

May we list your name in the collection (at the web site), to give you credit for providing this information?
If yes, how would you like your name listed? ("handles" ok.)
yes
TI-85: Jen Lemmer
TI-86: Le T

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Last update: September 28, 2011