## Sunday, December 16, 2018

### Retro Review: Texas Instruments Explorer Plus

Retro Review:  Texas Instruments Explorer Plus

General Information

Company:  Texas Instruments
Type:  Scientific - Algebraic
Display:  10 digits or 5 digits with 2 digit exponents
Power:  Solar
Memory:  1
Years:  1995 - 1997 (two editions).  I have a the 2nd edition.
Original Cost: \$24.95
Documentation:  Manual
Datamath page:  http://www.datamath.org/Sci/Modern/TI-32EXPLUS_2.htm

Features
* Trigonometry, Logarithms
* 1 Variable Statistics
* Backspace key
* Fractions with simplification
* 2 Stored Operations (Macros)
* Random Numbers
* Factorial, Combinations (nCr), Permutations (nPr)

Fractions

The Explorer Plus dedicates six keys to fractions.

[Unit]:  Enter the unit portion of a mixed fraction.  A small "u" separates the whole unit and its fraction.

[ / ]:  Use this to separate a fraction's numerator and denominator.  This is not the same as the division key [ ÷ ].

[ F <> D]:  Change a result from fraction to decimal and vice versa.  Changing to a fraction is does not always change the decimal to the fraction

[ A b/c ]:  Change an improper fraction to a mixed fraction.

[ x<> y ]:  Exchange entries.  This works for operations outside the fraction commands.

Changing to a mixed fraction with the [ A b/c ] key

Example:  Change the improper fraction 74/11 to a mixed fraction.

Keystrokes:  74 [ / ] 11 [ A b/c ]

Result:  6 u 8/11

Simplifying a Fraction

If a result has the display "N/D → n/d" on the left side, this means the fraction can be simplified.  Fractions can be fully simplified, or you can provide a factor.

Example:  Fully simplify 88/55.

Keystrokes: 88 [ / ]  55 [ = ] [Simp] [ = ]

Result: 8 / 5

Press [ x<>y ] to get the factor used to reduce the fraction, in this case, it would be 11.

Example:  Reduce the fraction 284/404 by a factor of 2.

Keystrokes:  284 [ / ] 404 [ = ] [Simp] 2 [ = ]

Result:  142 / 202

π and Fractions

In Radians Mode, you can work with fractions involving π.  The display will show "Pi".

Example:  π/4 + 3π/6

Keystrokes:  [ 2nd ] [ π ] (DR>) until RAD shows in the display

[ π ] [ / ] 4        Display:  Pi/4
[ + ] 3 [ π ] [ / ] 6      Display:  3Pi/6
[ = ]     Display:  9Pi/12

Result: 9π/12

For the decimal answer, press [ F<>D ] to get 2.35619449.

Other Keys of Interest

Integer Division

The integer division [ INT÷ ] will display the quotient and remainder of the division problems of two integers.  The displays the quotient by Q and remainder by R.  If you use the result in future calculations, only the integer portion is carried over.

Example:  Use the integer division command on 128 ÷ 35

Keystrokes:  128 [ INT÷ ] 35 [ = ]

Result:  Q:  3,  R:  23

Random Numbers

The RAND command on the Explorer Plus has two functions:

RAND by itself:  a three digit number between 0.000 and 0.999.  Press [ 2nd ] [ = ] (RAND)

Integer Random Number:  You can get a random integer from 1 to n (up to 100) by the this keystroke sequence:  1 [ 2nd ] [ = ] (RAND) n [ = ].

Example:  Generate a random integer from 1 to 50.

Keystrokes:  1 [ 2nd ] [ = ]  (RAND) 50 [ = ]

Results may vary.

Stored Operations

You can store simple operations in one of two OP registers, OP1 and OP2.  The operations that can be included are +, -, *, ÷, y^x, INT÷, y^(1/x), nCr, nPr, and random numbers.

Example:  Store x + 6 in OP1.

[CE/C] (or suitable number) [ + ] 6 [ OP1 ]

11 + 6, 15 + 6, 28 + 6

11 [ OP1 ]  Display:  1        17
15 [ OP1 ]  Display:  1       21
28  [ OP1 ] Display:  1      34

You can repeat operations.

Clear stored operations by either pressing [ON/AC], which will clear everything, or pressing [2nd] (

Verdict

I really like the the Explorer Plus and I think it would have a made a great base for the current TI-30X generation.  Texas Instruments could have used the TI-40 College (France), which added the rectangular/polar and degrees/degrees-minute-seconds conversion, along with the DIV command (don't know what that does).

This is a solid calculator for a basic scientific calculator.  I like the emphasis on fractions and it contains the basic scientific calculator functions.

Eddie

All original content copyright, © 2011-2018.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.  Please contact the author if you have questions.

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