Fun with the Radio Shack EC-4026

Fun with the Radio Shack EC-4026 

(Equivalent of the Casio fx-4500P)

Programming Notes

 

The syntax for prompting for variables and displaying results are slightly different from the usual Casio programming language (as I mentioned, the EC-4026 is a clone of the fx-4500P).  Check out the unusual If-Then-Else-End structure as well. 

Prompting Syntax:

{var} : var “prompt string”

Example:

 {X}: X”ENTER X”

Display Syntax:

Calculation

“Display string” ◢  (solid right triangle, [2ndF] [↑])

Example: 

X

“F(X)=” ◢

The If-Then-Else-End Structure:

If condition ⇒ do if the condition is true ⇏do if condition is false ◺  (clear right triangle, [2ndF] [√])

Note:  I symbolize the [x^y] by ^.

Finding the Monthly Payment of a Mortgage with Total Interest Paid and Total Cash Outflow

Program MORTGAGE:

L1  Fix 2

L2 {A}: A”LOAN AMOUNT”

L3 {Y}: Y”YEARS”

L4 {I}: I”RATE”

L5 I = I/1200

L6 N = Y*12

L7 P = A*(I(1+I)^N)/((1+I)^N-1)

L8 “MONTHLY PMT” ◢

L9 N*P

L10 “OUTFLOW” ◢

L11 N*P-A

L12 “TOTAL INTEREST” ◢

L13 Norm

Example:

A:  Loan is $250,000.00

Y:  30 years

I: Interest rate of 4%

Results:

P:  Payment:  $1,193.59

Outflow:  $429,673.77

Total Interest:  $179,673.77

Midlength, Height, and Area of a Trapezoid

Program TRAPEZIOD:

L1 {A}

L2 {B}
L3 {C}

L4 {D}

L5 H = √((-A+B+C+D)*(A-B+C+D)*(A-B+C-D)*(A-B-C+D))/(2*Abs(B-A))

L6 M = (A+B)/2

L7 K = M*H

L8 M

L9 “MIDLENGTH” ◢

L10 H

L11 “HEIGHT” ◢

L12 K

L13 “AREA” ◢

Quadratic Equation A*x^2 + B*x + C = 0

Program QUAD:

L1 {A}: A”A”

L2 {B}: B”B”

L3 {C}: C”C”

L4 D = B^2-4*A*C

L5 D<0 ⇒ Goto 1 ◺

L6 X = (-B + √D)/(2A) ◢

L7 Y = (-B - √D)/(2A) ◢

L8 Goto 0

L9 Lbl 1

L10 X = -B/(2A)

L11 “REAL” ◢

L12 Y = √(Abs D)/(2A)

L13 “IMAG” ◢

L14 Lbl 0

L15 “DONE” ◢

Example:

3x^2 + 6x – 1 = 0; A = 3, B = 6, C = -1

Result:  0.154700538, -2.154700538

3x^2 + 6x + 10 = 0; A = 3, B = 6, C = 10

Result:  REAL: -1, IMAG: 1.527525232.  -1 ± 1.527525232i

Minimum Loss Matching

Variables:

Input: Y = Z0, Z = Z1

Output:

R = R1

S = R2

L = Loss Marching

Program MINLOSS:

L1 1:  “Z1<Z0” ◢

L2 {Y}: Y”Z0”

L3 {Z}: Z”Z1”

L4 L = √(1 – Z/Y)

L5 R = Y*L: “R1”◢

L6 S = Z/L: “R2” ◢

L7 L = 20 log (√(Y/Z) + √(Y/Z – 1)): “LOSS” ◢

Example:

Input:

Y: Z0: 15

Z: Z1: 10

Output:

R1: 8.66025 Ω

R2:  17.32051 Ω

Loss:  5.71948

Add Two Polar Numbers

Polar and Rectangular conversions

Variable	Rectangular Results	Polar Results
V	x	r
W	y	θ

Program ADDPOLAR:

L1 {R}: R”R1”

L2 {S}: S”ANG1”

L3 Rec(R,S)

L4 R = V: S = W

L5 {V}: V”R2”

L6 {W}: W”ANG2”

L7 Rec(V,W)

L8 R = R+V: S = S+W

L9 Pol(R,S)

L10 V: “R SUM”◢

L11 W: “ANG SUM”◢

Example:

4 ∠ 20° + 3 ∠ 11 ° (In Degrees Mode)

Result (rounded to 4 digits): 6.9789 ∠ 16.1442°

How to Handle a Tax Bracket (Simple Sample)

Take a sample (and simplified) tax bracket, where income is X:

0 < X ≤ 200:  tax rate is 10% of X

200 < X ≤ 600:  tax rate is 13% of X

600 < X: tax rate is 16% of X

Program:

L1 {X}: X”X”

L2 X > 600 ⇒ P = 16: Goto 1 ◺

L3 X > 200 ⇒ P = 13: Goto 1 ◺

L4 P = 10

L5 Lbl

L6 X * P/100

Eddie

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