Fun with the TI-81 (March 2024 Edition)
TI-81 SCATTER
Produces a scatter plot.
Size: 52 bytes
Code:
If Dim{x}=0
Disp “NO DATA”
If Dim{x}=0
Stop
ClrDraw
1→I
Lbl 0
PT-On({x}(I),{y}(I))
IS>(I,Dim{x})
Goto 0
DispGraph
Note: Dim{x} returns the number of data points in the statistics list {x}.
Keystrokes: [ VARS ], DIM, 7: Dim{x}
TI-81 ANGLES
Given three pints, the internal and external angle are calculated.
Size: 196 bytes
Code:
Deg
Disp “SIDE PT (S,T)”
Input S
Input T
Disp “CORNER (M,N)”
Input M
Input N
Disp “SIDE PT (U,V)”
Input U
Input V
(S-M)*(U-M)+(T-N)*(V-N)→D
√((S-M)^2+(T-N)^2)→A
√((U-M)^2+(V-M)^2)→B
cos^-1 (D/(A*B))→I
360-I→E
Disp “INTERNAL ANGLE”
Disp I
Disp “EXTERNAL ANGLE”
Disp E
Example:
(S,T) = (-4,-6)
(M,N) = (1,1)
(U,V) = (3,5)
INTERNAL ANGLE: 171.0273734
EXTERNAL ANGLE: 188.9726266
Source:
Cook, John D. “Ramanujan approximation for circumference of ellipse” John D. Cook Consulting. May 5, 2015. https://www.johndcook.com/blog/2013/05/05/ramanujan-circumference-ellipse/ Accessed January 24, 2024
TI-81 ELLIPSE
Given the length of the semi-axis, the program draws the ellipse, calculates the area, and approximates the circumference using Ramanujan formula.
Size: 195 bytes
Code:
Param
Rad
Disp “SEMI X-AXIS”
Input A
Disp “SEMI Y-AXIS”
Input B
(A-B)/(A+B)→L
π*(A+B)*(1+(3*L^2)/(10+√(4-3*L^2))→P
π*A*B→R
Disp “APPROX. CIR=”
Disp P
Disp “AREA=”
Disp R
Pause
All-Off
“A*cos T”→X_1T
“B*sin T”→Y_1T
X1T-On
-A-1→Xmin
A+1→Xmax
-B-1→Ymin
B+1→Ymax
0→Tmin
2π→Tmax
π/24→Tstep
DispGraph
Notes:
All-Off turns all the graphing equations off from graphing.
[ 2nd ] {Y-VARS}, OFF, 1: All-Off
XT1 and YT1 are the equation variables x1(t) and y1(t):
[ 2nd ] {Y-VARS}, Y, 5: X_1T and 6: Y_1T, respectively
Example:
SEMI X-AXIS? 2
SEMI Y-AXIS? 3
Results:
APPROX. CIRC= 15.86543959
AREA= 18.84955592
TI-81 RELATIVE
Calculate the consequences of reality when it comes to a length and mass of an object traveling near the speed of light, c = 299,792,458 m/s.
Size: 141 bytes
Code:
299792458→C
Disp “C=”
Disp C
Disp “M/S”
Pause
Disp “°/. OF C”
Input P
P*C/100→U
√(1-(U/C)^2)→V
Disp “LENGTH”
Input L
Disp “OBS LENGTH=”
L*V→K
Disp K
Pause
Disp “MASS”
Input M
Disp “OBS. MASS=”
M/V→N
Disp N
Enter the percentage of the speed of light (70%, 80%, 90%, etc.). Three characters are used to create the percent sign (%) (°, / , . )
Example:
92.5% of the speed of light
length: 40.8 m
mass: 6,700 kg
Results:
observed length = 15.50265784 m
observed mass = 17,633.10542 kg
Source:
Jackson, Mark D. The QuickStudy for Physics BarCharts Publishing Inc. Boca Raton, Florida. 2007. ISBN 13: 9781423202677. pp. 114-115
Eddie
All original content copyright, © 2011-2024. 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.
