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
* Degree and Radian mode
* 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

[ Simp ]:  Use this key to simplify fractions.  I'll talk about this in a bit.

[ 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

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