Fun with the Texas
Instruments TI60
Notes:
1. I like to have the
user input all the values into the registers before running the program. This way, we can save program steps because
the calculator doesn’t have to stop to ask for inputs. Also, you don’t have to change all the values
for different problems. Finally, R/S can
be used for only output.
2. I keep register 0
(R0) out so that the user can have at least one register to store immediate
results in further calculations. I list
the minimum partition for each program.
Great Circle Distance (in miles)
Formula:
D = acos (sin ϕ1 * sin ϕ2 + cos ϕ1 * cos ϕ2 * cos (λ1 – λ2))
* 3959 * π/180
Note: for kilometers, replace 3959 with 6371.
Where:
ϕ1, ϕ2: Latitude of
locations 1, 2; north is positive, south is negative
λ1, λ2: Longitude of
locations 1, 2: east is positive, west
is negative
Store before running:
R1: ϕ1 as a decimal
(convert from DMS if necessary)
R2: λ1
R3: ϕ2
R4: λ2
Set the TI60 in degrees mode.
Program (41 steps) – 2nd Part 5:
PG

OP

Key

PG

OP

Key

00

71

RCL

21

04

4

01

01

1

22

54

)

02

32

SIN

23

33

COS

03

65

*

24

95

=

04

71

RCL

25

12

INV

05

03

3

26

33

[COS] (COS^1)

06

32

SIN

27

65

*

07

85

+

28

03

3

08

71

RCL

29

09

9

09

01

1

30

05

5

10

33

COS

31

09

9

11

65

*

32

65

*

12

71

RCL

33

91

π

13

03

3

34

55

÷

14

33

COS

35

01

1

15

65

*

36

08

8

16

53

(

37

00

0

17

71

RCL

38

95

=

18

02

2

39

13

R/S

19

75



40

22

RST

20

71

RCL




Example:
Los Angeles: ϕ =
34°13’ = 34.21666667°, λ = (118°15’) = (118.25°)
London: ϕ = 51°30’26”
= 51.50722222°, λ = (0°7’39”) = (0.1275°)
Result: 5431.617778
mi
Tip: For DMSDD conversions: if you have a negative angle,
enter the angle without the negative sign, do the conversion DMSDD, then press [ +/ ].
Impedance of a Series Resonance Circuit
This program gives both the magnitude and phase angle.
Impedance: Z = R +
j*(ω*L – 1/(ω*C))
Where: ω = 2*π*F
Magnitude: abs(Z)
Phase Angle: arg(Z)
Variables:
R = resistance ( Ω )
C = capacitor ( farads )
L = inductor ( henrys )
F = Frequency (Hz)
Store before running:
R1: R
R2: C
R3: L
R4: F
Set the TI60 in degrees mode.
Program (35 steps) – 2nd Part 5:
PG

OP

Key

PG

OP

Key

00

02

2

18

02

2

01

65

*

19

54

)

02

91

π

20

76

1/x

03

65

*

21

95

=

04

71

RCL

22

61

STO

05

04

4

23

05

5

06

95

=

24

71

RCL

07

61

STO

25

01

1

08

05

5

26

52

X<>Y

09

65

*

27

71

RCL

10

71

RCL

28

05

5

11

03

3

29

12

INV

12

75



30

38

[PR]
(RP)

13

53

(

31

13

R/S

14

71

RCL

32

52

X<>Y

15

05

5

33

13

R/S

16

65

*

34

22

RST

17

71

RCL




Example:
Input:
R1: R = 11.56 Ω
R2: C = 0.0002 F
R3: L = 0.018 H
R4: F = 72 Hz
Results:
Phase Angle (θ) = 14.12679136°
Magnitude = 11.92049981
Linear Interpolation
Given points (x0, y0) and (x1, y1) with x0 < x < x1,
we can estimate y by linear interpolation by:
y = ((x1 – x)*y0 + (x – x0)*y1)/(x1 – x0)
How good of an approximation depends on how close x0 and x1
are, and whether the curve that is being approximated is close to linear.
Store before running:
R1: x1
R2: y1
R3: x2
R4: y2
R5: x
Program (34 steps) – 2nd Part 5:
PG

OP

Key

PG

OP

Key

00

53

(

17

01

1

01

53

(

18

54

)

02

71

RCL

19

65

*

03

03

3

20

71

RCL

04

75



21

04

4

05

71

RCL

22

54

)

06

05

5

23

55

÷

07

54

)

24

53

(

08

65

*

25

71

RCL

09

71

RCL

26

03

3

10

02

2

27

75



11

85

+

28

71

RCL

12

53

(

29

01

1

13

71

RCL

30

54

)

14

05

5

31

95

=

15

75



32

13

R/S

16

71

RCL

33

22

RST

Example:
Input:
R1: x1 = 2
R2: y1 = 3
R3: x2 = 4
R4: y2 = 8
R5: x = 3
Result:
y = 5.5
Purchase of a Car:
How much can I afford?
The program will calculate the sticker price (price before
sales tax) of an automobile that you can afford. You give the term you want, the interest rate
you qualify for, the sales tax rate, and the maximum payment you can afford. This assumes that you don’t put any money
down.
Formulas:
A = P/I * (1 – (1 + I)^N) / (1 + S)
A = sticker price of the car
P = monthly payment
I = monthly interest rate of the loan, in decimal. I = rate/1200
N = number of months.
N = years*12
S = sales tax rate, in decimal. S = sales tax rate/100
Input:
R1: number of
payments
R2: monthly interest
rate
R3: payment
R4: sales tax rate,
in decimal
Program (30 steps), 2nd Part 4:
PG

OP

Key

PG

OP

Key

00

71

RCL

15

45

y^x

01

03

3

16

71

RCL

02

55

÷

17

01

1

03

71

RCL

18

94

+/

04

02

2

19

54

)

05

65

*

20

55

÷

06

53

(

21

53

(

07

01

1

22

01

1

08

75



23

85

+

09

53

(

24

71

RCL

10

01

1

25

04

4

11

85

+

26

54

)

12

71

RCL

27

95

=

13

02

2

28

13

R/S

14

54

)

29

22

RST

Example:
Input:
R1: number of
payments = 60, (5 year term)
R2: monthly interest
rate = 0.05/12 = 0.004166667, (5% annual interest rate)
R3: payment = 400
R4: sales tax rate,
in decimal = 0.095, (9.5%)
Result: 19357.34
In this example, the highest sticker price that can be
afforded is $19,357.34 (before sales tax).
I enjoy programming with the TI60, unlike most Texas
Instruments calculators that have keystroke programming, the TI60 shows the
step and key code you have entered instead of advancing to the next step with
code 00.
Eddie
This blog is property of Edward Shore, 2018.
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