Retro Review: Texas Instruments Galaxy 40sx
Quick Facts
Model: Texas Instruments Galaxy 40sx
Company: Texas Instruments
Years: 1991 (early 1990s)
Type: Scientific
Power: Solar Power
Display: 1 line, 10 digits
Memory Register: 1
Operating System: Algebraic (prefix, AOS)
Features
The TI-Galaxy 40 sx is a landscape, scientific calculator which has the basic scientific calculator features plus several extras:
* Trigonometry. There are two angle modes: degrees and radians.
* 1-variable statistics
* Polar/Rectangular Conversion
* Powers, Roots, Logarithms, Exponentials
* Factorial of positive integers to 69
* Scientific notation and cancellation of the scientific notation view mode
* Two single-operation macros
The calculator is protected by a hard slide case, which slides on and off.
The [ -x ] is the change sign key.
The Galaxy 40 sx is the solar-powered version of the Galaxy 40 sx.
Parenthesis
When the parenthesis keys [ ( ] and [ ) ] are pressed, the calculator keeps track of open parenthesis on the screen.
For example: (( 2 + 1.8 ) ÷ 3 )^3 ≈ 2.032296296
[ ( ] [Screen: ( One open level.]
[ ( ] [Screen: ( ( Two open levels.]
2 [ + ]
1.8 [ ) ] [Screen: ) flashes, then shows 3.8. One open level left.]
[ ÷ ] 3
[ ) ] [Screen: 1.266666667]
[ 2nd ] (y^x)
3 [ = ] [Screen: 2.032296296]
Fractions
The Galaxy 40sx has an emphasis on fractions:
[ |- ]: Euclidean Division. This function divides two integers and shows the quotient and remainder.
Example:
148 [ |- ] 39 [ = ] : Q: 3 R : 31
Entering Fractions:
[ u ]: Unit (whole number)
[ / ]: Fraction key. Enter the numerator, press [ / ], then enter the denominator.
Example:
Enter 5 4/9. 5 [ u ] 4 [ / ] 9 [ = ]: 5 u 4/9
[ F<>D ]: Fraction/Decimal Conversion. The algorithm is not perfect as if has a hard time converting many digits to fractions. For example: 1.666666667 does not convert to 5/3. 0.142857143 does not convert to 1/7. Your mileage may vary.
[ F→A b/c ]: Converts an improper fraction to a mixed fraction.
Example:
427/19. 427 [ / ] 19 [ F→A b/c ]: 22 u 9/19
[ SIMP ]: Simplify fractions. When N/D→n/d appears on the left hand the screen, the displayed fraction can be simplified. You can choose the factor or let the calculator choose the factor.
To choose the factor, press [ SIMP ], enter a factor, then press [ = ].
To have the calculator choose the factor, press [ SIMP ], then press [ = ].
In either case, you can view the factor used by pressing [ 2nd ] [ SIMP ] (DIV). To continue simplifying, press [ x<>y ] to get the fraction back on the screen.
Example: Let the calculator choose the factor.
24/88.
[ SIMP ] [ = ]: 12/44. [ 2nd ] [ SIMP ] (DIV): 2
[ x<>y ]
[ SIMP ] [ = ]: 6/22. [ 2nd ] [ SIMP ] (DIV): 2
[ x<>y ]
[ SIMP ] [ = ]: 3/11. [ 2nd ] [ SIMP ] (DIV): 2
A fraction is irreducible when N/D→n/d is no longer on the screen.
Memory Arithmetic
The Galaxy 40sx has one memory register.
[ STO ]: Store number into the memory register.
[ RCL ]: Recall the number from the memory register.
[ SUM ]: Adds the number to the memory register. (STO+)
[ 2nd ] [ STO ] (EXC): Exchanges the number in the memory with the contents of the memory register.
Single-Operation Macros
The Galaxy 40sx has two single-operation macros: OP1 and OP2. The operations can be stored are:
[ + ] n : Addition
[ - ] n : Subtraction
[ × ] n : Multiplication
[ ÷ ] n : Division
[ y^x ] n : Power
[ ˣ√ ] n : Roots (principal roots)
Storing each macro will also display any arithmetic operation, which is nice.
Pressing [ 2nd ] (<OP1) or (<OP2) clears the macro.
This allows for repeated calculations.
Example: Square 4, 7, and 11.
[ AC/ON ] [ 2nd ] [ x^2 ] (y^x) [ OP1 ]
4 [ OP1 ]: Display 1 16 (answer: 16, 1st step)
7 [ OP1 ]: 49
11 [ OP1 ]: 121
Note: When executing macros, there is a number on the left that indicates the number of times [ OP1 ] or [ OP2 ] has been pressed repeatedly, until 10 or more digits of the answer is displayed. I find that potentially confusing.
Final Thoughts
I like the keyboard. I wish the calculator had a full-simplification function as an option. I would also love to see the SIMP key double as a prime factorization of an integer. The parenthesis tracker and operation macros are nice.
The calculator works best in full light and has some extra features above the basic scientific calculator.
Source
Datamath. "Texas Instruments Galaxy 40sx" Last Updated December 5, 2001. Retrieved August 14, 2023. http://www.datamath.org/Sci/Galaxy/TI40_Galaxy.htm
The manual that can be downloaded is in Dutch.
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