Fun with the TI-80
TI-80 Program D2DMS -
Decimal to Degrees-Minutes-Seconds
Variables:
Decimal Format:
D = decimal
DMS Format:
H = degrees/hours, M = minute, S = seconds
INPUT “DEC:”,D
IPART D→H
IPART (60*FPART D)→M
60 * FPART (60 * FPART D)→S
DISP “H,M,S:”,H,M,S
TI-80 Program DMS2D -
Degrees-Minutes-Seconds to Decimal
Variables:
Decimal Format:
D = decimal
DMS Format:
H = degrees/hours, M = minute, S = seconds
INPUT “H:”,H
INPUT “M:”,M
INPUT “S:”,S
H + M/60 + S/3600 → D
DISP “DEC:”,D
TI-80 Program QUADRAT
- Quadratic Equation
Variables:
A, B, C are coefficients of the equation Ax^2 + Bx + C,
where the discriminant D:
D = B^2 – 4*A*C
If D≥0, then the roots are real and stored in X and Y.
If D<0, then the roots are complex and are in the form of
conjugates X ± Yi. X is the real part, Y
is the imaginary part.
DISP “AX^2+BX+C=0”
INPUT “A:”,A
INPUT “B:”,B
INPUT “C:”,C
B^2 – 4AC → D
DISP D
-B / (2A) → E
IF D≥0
THEN
E + √D/(2A) → X
E - √D/(2A) → Y
DISP “R1:”,X
DIPS “R2:”,Y
ELSE
E → X
√-D / (2A) → Y
DISP “RE:”,X
DISP “IM :”,Y
END
Annuity Factors
Variables:
I = periodic interest rate
N = number of payments/periods/deposits
TI-80 Program USFV –
Annuity Future Value Factor
INPUT “I:”,I
INPUT “N:”,N
( (1+.01)^N – 1)/(.01I) → F
DISP F
TI-80 Program USPV –
Annuity Present Value Factor
INPUT “I:”,I
INPUT “N:”,N
(1 – (1 + .01I)^-N)/(.01I) → P
DISP P
Two Dimensional
Vector Operations
Let two vectors be defined as V1 = [A, B] an V2 = [C,
D]. The program calculates the dot
product, stored in E, norm of V1, stored in F, norm of V2, stored in G, and the
angle between V1 and V2 in degrees, stored in H.
TI-80 Program VECTOR2
DEGREE
DISP “V1:”
INPUT A
INPUT A
INPUT B
DISP “V2:”
INPUT C
INPUT D
AC + BD → E
√(A^2 + B^2) → F
√(C^2 + D^2) → G
COS^-1 (E /(F*G)) → H
DISP “NORM V1:”, F
DISP “NORM V2:”, G
PAUSE
DISP “DOT:”, E
DISP “ANGLE:”, H
Simplistic Logistic
Regression
Fit data (x,y) to the equation:
Y = 1 / (A + B*e^(-X))
TI-80 Program SIMPLOG
INPUT “L1:”, L1
INPUT “L2:”, L2
e^-L1 → L1
1/L2 → L2
LINREG(aX+b) L1, L2
a→A: b→B
DISP “1/(B+Ae^X)”,A,B
PAUSE
DISP “CORR^2”,r^2
Eddie
This blog is property of Edward Shore, 2017
