**TI-74 Programming: Factorial, List of Random Integers, 2 x 2 Matrix Determinant and Inverse, Simple Pendulum, Secret Codes**

Note: The TI-74 has one programming space (lines 0
to 32768), which the entire space can be saved if the TI-74 connected to an
appropriate peripheral (cassette or computer).
Cassettes? The TI-74 is a 1980s
basic computer after all.

**TI-74 Program Factorial**

The TI-74 does
not have a factorial function its command set.
Here is one way to tackle it:

1300 !
Factorial

1310 INPUT “N=”;
N

1320 IF N=0
THEN PRINT 0: PAUSE: STOP

1325 F=1

1330 IF I=1 TO
N-1

1340 F=F*I

1350 NEXT I

1360 PRINT “N!=”;
F: PAUSE

1370 END

**TI-74 List of Random Integers**

Integers will
appear for 2 seconds followed by a “Next…” indicator.

1000 ! List of random
integers

1005 RANDOMIZE

1010 INPUT “Length?”;
K

1020 INPUT “High
Number:”; N

1025 FOR I=1 TO
K

1035 PRINT INT(N*RND+1):
PAUSE 2

1040 PRINT “Next…”:
PAUSE 0.5

1045 NEXT I

1050 PRINT “Done”:
PAUSE: END

**TI-74 2 x 2 Matrices: Determinant and Inverse**

Matrix: [[A, B],[C, D]]

Inverse: [[F, G],[H, I]]

Determinant: E
= A*D – B*C. If E=0, the matrix is
singular.

1100 ! 2 x 2
Matrices; det/inv

1105 INPUT “A=”;
A, “B=”; B

1110 INPUT “C=”;
C, “D=”; D

1115 E=A*D-B*C

1120 PRINT “det=”;
E: PAUSE 2

1125 IF E=0
THEN STOP

1130 PRINT “inv=”:
PAUSE 2

1135 F = D/E: G
= -B/E: H=-C/E: I=A/E

1140 PRINT “F=”;
F: PAUSE 2

1145 PRINT “G=”;
G: PAUSE 2

1150 PRINT “H=”;
H: PAUSE 2

1155 PRINT “I=”;
I: PAUSE 2

1160 END

Example:

Matrix: [[1, 5],[-2, 7]]

A=1, B=5, C=-2, D=7

RUN 1100:

det = 17

inv =

F = .4117647059

G =
-.2941176471

H = .1176470588

I = .0588235294

**TI-74 Simple Pendulum: Angular Velocity and Period**

This routine
calculates the angular velocity and period for a simple pendulum. SI units are used, meaning that g = 9.80665
m/s^2. Note the SQR command is square
root.

1200 ! Simple
Pendulum, SI unites

1205 G=9.80665

1210 INPUT “Length
(m):”; L

1215
W=SQR(G/L): T=2*PI*SQR(L/G)

1220 PRINT “Angular
Vel.:”; W; “m/s”: PAUSE

1225 PRINT “Period:”;
T; “s”: PAUSE

1230 END

Example: L = 1.14 m

Results: W = 2.932971967 m/s, T = 2.1422588902 s

**TI-74 Secret 3 Digit Codes**

I learn the
PRINT USING and IMAGE commands for the first time here. On the TI-74, # is a number field, the period
(.) is the decimal point, ^ is the exponential character, and I can use spaces
and text. Yes, IMAGE is different on each
of the basic calculators.

500 IMAGE ###
### (3 spaces in between the
sets of hashtags)

505 PRINT “Here are the”: PAUSE 1

510 PRINT “secret codes!”: PAUSE 1

515 FOR I=1 TO 4

520 A=100*RND:
B=100*RND

525 PRINT USING
500; A,B : PAUSE 1

530 NEXT I

540 END

**Notes**

1.
I am not able to use a variable while using a
DIM command to size an array. This is
not allowed:

100 Z = 10

110 DIM A(Z)

2.
The commands and one-letter variables auto-capitalize
when [ENTER] is pressed. For example:

I type 100 print a, press [ENTER] and when look at the line again, the TI-74
displays:

100 PRINT A

3.
It is a good idea to put an END command after
each routine. END will tell the TI-74
stop, allowing multiple, separate routines in the TI-74 programming space.

4.
The
amount of free memory is found by the formula:
FRE(0)-FRE(1). The keyboard
shortcut to FRE is [FN] [ ↓ ].

5.
If
you want to clear the entire program space, type NEW ALL.

There will be
more TI-74 programs in the near future.
Until next time,

Eddie

This blog is
property of Edward Shore, 2016.

This code is short and very easy to understand. As to perform the operations like factorial & matrix with online tools like calculate factorial is pretty easy but now with the use of your information, one can also create their own program to find out the factorial and matrix of various numbers. Great work!!!

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