I like old calculators. I also like solar calculators since I don't like to change batteries. The calculator I've used for the longest time is the TI 30 SLR which came out in 1982. I think it's cool to use something that's like 40 years old and has never needed a change of batteries. I love that calculator. I can entertain myself for hours just pressing random buttons on it.

Then one day I was browsing through the datamath calculator museum (easy to go into a rabbithole there) for some reason when I found the TI-37 Galaxy Solar. It was solar, it had more digits (especially with scientific notation), it had different bases, hyperbolic tric functions, statistics stuff, etc. It seemed like just the TI 30 SLR but with more features. So after a while of looking at ebay, I bought a TI 52 solar. The TI 52 and the TI 37 Galaxy are identical. I don't know why the names are different.

The first thing I noticed, though, was that there were so many new functions and I didn't know what a lot of them did! So I played around with it and looked stuff up online until I figured *most* of them out. I'll document them on this page. Click a key on the picture to jump to the different functions it does! All the entries that follow will be from left to right, top to bottom. There are still a bunch of functions that I have no idea about. Help me. It's like a CIA prison. The functions are: FD, Sci, Eng, >DD, >DMS, P(t), R(t), Q(t), σn-1, nCr, and nPr. What do they do?????? I assume >DD and >DMS have something to do with conversion between degrees-minutes-seconds but idk that. Sci and Eng probably deal with the exponent? And the rest is statistics???? Not sure

2nd

Toggles between regular and 2nd mode. The 2nd indicator will be lit on the screen when active

LOG ; 10^x

Computes log₁₀ of the displayed number
2nd operation: Computes 10^x of the displayed number

LNx ; e^x

Computes natural log of the displayed number. The natural log is just the base-e logarithm.
2nd operation: Computes e^x of the displayed number

y^x ; x-th root of y

Computes y^x with the displayed number
2nd operation: Computes the x-th root of y with the displayed number

->

Backspace; removes the last digit you typed in

( ; Fix

Opens a parenthesis
2nd operation: 'Fix' the display to a certain number of decimal places. After pressing this, the next number entered will become the number of decimal places to round to

) ; Rnd

Closes a parenthesis
2nd operation: Enters a random 3 decimal place number, between 0 and 1

AC

Completely reset the calculator

CE/C

Clear the entry

x² ; sqrt x

Computes x²
2nd operation: Computes sqrt of x

1 over x ; cbrt x ; D

Computes the reciprocal of x
2nd operation: Computes the cube root of x
Hex mode: Enters the hex digit D

a ; P>R ; E

Dunno (please help)
2nd operation: Dunno (please help)
Hex mode: Enters the hex digit E

b ; R>P ; F

Dunno (please help)
2nd operation: Dunno (please help)
Hex mode: Enters the hex digit F

7 ; P(t)

Enters the digit 7
2nd operation: Dunno (please help)

8 ; R(t)

Enters the digit 8
2nd operation: Dunno (please help)

9 ; Q(t)

Enters the digit 9
2nd operation: Dunno (please help)

÷ ; nCr

Divides numbers
2nd operation: Dunno (please help)

HYP ; -1

Toggles between the trig functions being hyperbolic
2nd operation: Dunno (please help)

SIN ; -1 ; A

Computes the sine (sin) or hyperbolic sine (sinh) of x
2nd operation: Computes the inverse sine (arcsine, asin, sin^-1) or inverse hyperbolic sine (arcsinh, asinh, sinh^-1) of x
Hex mode: Enters the hex digit A

COS ; -1 ; B

Computes the cosine (cos) or hyperbolic cosine (cosh) of x
2nd operation: Computes the inverse cosine (arccos, acos, cos^-1) or inverse hyperbolic cosine (arccosh, acosh, cosh^-1) of x
Hex mode: Enters the hex digit B

TAN ; -1 ; C

Computes the tangent (tan) or hyperbolic tangent (tanh) of x
2nd operation: Computes the inverse tangent (arctan, atan, tan^-1) or inverse hyperbolic tangent (arctanh, atanh, tanh^-1) of x
Hex mode: Enters the hex digit C

4 ; mean of x ; HEX

Enters the digit 4
2nd operation: In statistics mode, compute the mean of the data
Mode selection: HEX

5 ; σn-1 ; CPLX

Enters the digit 5
2nd operation: In statistics mode, compute the sigma n - 1 of the data
Mode selection: Complex numbers

6 ; σn

Enters the digit 6
2nd operation: In statistics mode, compute the standard deviation of the data

x ; nPr

Multiplies numbers
2nd operation: Compute the nPr function of the numbers inside a and b.

= ; %

Computes the result of any pending operations
2nd operation: Calculates percentages. Punch in 200 + 3%, for example, and the 3% will automatically become 6 (which is 200 * 0.03)

EXP ; π

Edit the scientific notation exponent
2nd operation: The pi constant 3.141592654

DRG ; >

Switch the calculator between using degrees, radians, and graduations
2nd operation: Convert the displayed number between degrees, radians, and graduations

Int ; Frac

Compute the integer part of the displayed number (floor it)
2nd operation: Compute the decimal part of the displayed number

Σ+ ; Σ-

In statistics mode, add data
2nd operation: In statistics mode, remove data

1 ; Σx ; DEC

Enter the digit 1
2nd operation: In statistics mode, calculate the sum of the data
Mode selection: Decimal (the default)

2 ; Σx² ; BIN

Enter the digit 2
2nd operation: In statistics mode, calculate the sum of the data squared
Mode selection: Binary

3 ; n ; OCT

Enter the digit 3
2nd operation: In statistics mode, enter the number of items in data
Mode selection: Octal

- ; >DMS

Subtract numbers
2nd operation: Dunno (please help)

STO ; EXC

Store the displayed value into memory
2nd operation: Swap the displayed value with the value in memory

RCL ; x><y

Enter the value stored in memory
2nd operation: Swap the displayed value with the value pending operation

SUM ; x!

Add the displayed value to the value stored in memory
2nd operation: Computes the factorial of x

MODE

After pressing, select a mode for the calculator

0 ; FD

Enters the digit 0
2nd operation: Dunno (please help)

. ; Sci

Enters a decimal point
2nd operation: Dunno (please help)

+/- ; Eng

Change the displayed number's sign
2nd operation: Dunno (please help)

+ ; >DD

Adds numbers
2nd operation: Dunno (please help)

Other stuff

Different bases: to select a base, press MODE and then the base you want (either HEX, DEC, OCT, or BIN). Converting a number between bases works the same way when the number you wanna convert is displayed. When not in base 10, many of the algebraic functions won't work, and you're left with basic calculator functions like + - / and ÷ until you go back to decimal. The memory will persist across different bases, however.

a, b, and polar to/from rectangular form: The a and b functions either store or view a number in a complex part. Even when not in CPLX mode, it can be used to convert complex numbers in polar form to or from rectangular form. You do this by storing numbers in a and b (by pressing them while a number is displayed) and then using either the P>R or R>P functions depending on whether it's Polar to Rectangular or vice versa. For a rectangular complex number a+bi, obviously a is a and b is b, and for a polar complex number, r is a and θ is b.

Example: convert 4+5i to polar form: enter 4 and press the 'a' key to store it in a. Then enter 5 and press the 'b' key to store it in b. Do the R>P function by pressing 2nd then pressing the b key. After this, r will be in a, and θ will be in b. The contents of a (r) should already be displayed, but you can press it anyways to see: 6.40312437. Then press b to view its contents (θ): 51.34019174. So 4+5i = 6.403e^i51.340 about.

Example 2: convert 7eⁱ¹²⁵ to rectangular form: similar to above, just put 7 into a and 125 into b. Then do the P>R function, on the 'a' key. You should get -4.015035054 in a and 5.73406431 in b. So 7eⁱ¹²⁵ = -4.015 + 5.734i about.

Of course, you probably shouldn't be too reliant on your calculator for something like this. The formula to convert from rectangular (a+bi) to polar form (re^iθ):
r = sqrt(a² + b²)
θ = tan^-1(^b/_a)
And the formula to convert polar form to rectangular:
a = r*cos(θ)
b = r*sin(θ)*i
Not gonna go into the trigonometric justification for them (mostly because I don't really know it). But there are lots of other places that talk about it. Also note that you can only really view the contents of a and b after performing a conversion, so probably don't try to use them as extra memory.

Complex number arithmetic: Although CPLX mode is recognized as another mode, you can still do a lot of the algebraic functions. But they apply to the displayed numbers only, not the complex numbers. So sadly this calculator can't do wacky stuff like the sine or log of imaginary numbers (although it's possible and pretty cool). But you can still add, subtract, multiply, and divide whole complex numbers. You do this by storing values in a and b as usual; but after you press +, -, x, or ÷, the display will reset, allowing you to store more values in a and b before you press =.

Example: compute (3+1i)*(4-8i): in complex mode, put 3 into a and 1 into b. Then press x to multiply. Then put 4 into a and -8 into b. Press =. You can now press a to view the result's a value (20) or press b to view the result's b value (-20). So (3+1i)*(4-8i) = 20-20i

Example 2: compute (5+2i)/(7+i): like above, but press / instead of x since you're dividing them. You should get 0.74 in a and 0.18 in b. So (5+2i)/(7+i) = 0.74+0.18i

Again you should probably know what's going on and how to multiply and divide complex numbers. To multiply, it's as simple as FOILing it out.

(3+1i)(4-8i)

12 - 3(8i)
   + 1(4i) - (1i)(8i)
---------------------
12 - 24i
   +  4i - 8i2
---------------------
12 - 20i + 8
---------------------
20 - 20i

SO

(3+1i)(4-8i)=20-20i

(5+2i)
------
(7+i)
**multiply top and bottom by conjugate (7-i):
(5+2i)(7-i)
-----------
(7+i)(7-i)
**FOIL them out:
37+9i
-----
 50
**split apart:
37    9
-- + -- i
50   50
**and there's the result. Note that it's in a+bi
**form, where a=37/50 and b=9/50.
37/50 = 0.74
 9/50 = 0.18

x><y function: this simply swaps the displayed number with the one that's pending operation. For example, press 2 then ÷ then 1. Upon pressing =, this would calculate 2÷1=2, right? But press the x><y button to swap the 2 and the 1. Now it'll calculate 1÷2=0.5

STAT mode: this is for doing stuff with statistics. In this mode, you can still use the calculator mostly as normal, but what's important is the list of data it'll now keep track of. You can add the currently displayed number to the list by pressing the Σ+ key; you can also add more of the same number by using the multiplication operator with it (press 2 then x then 3 then Σ+ to enter 2 3 times). Use Σ- to remove elements from the list. If there's a number currently displayed, it seems to try to remove the element at that position. You can use the n function to display the number of elements in the list in case it gets finicky. Anyways, once you input all your data, there's a few things you can do with it:

• calculate the average with x
• calculate the sum with Σx
• calculate the sum of the items squared with Σx²
• calculate standard deviation with σn
• view the number of items with n

nPr and nCr