7000G Retro Month - June 26 Edition
Introduction
Welcome to the 7000G Retro Month, which features programming for the classic Casio calculators from the mid/late 1980s: primarily fx-7000G and fx-7500G. Since the programming language stays similar throughout the years, programs can be translated to the fx-6300G and later graphing calculators with little to no adjustments. Non graphic programs should be ported to the fx-4000P, fx-4500P (A), fx-3650p (II), fx-50F Plus (II), and fx-5800P with little to no adjustments.
7000G Retro Month takes place every Saturday during June 2021.
To make text easier to type, I can going to use the following text friendly symbols for the following:
-> for →
/I for ⊿
=> for ⇒
What do you think? Unicode or simple text equivalents?
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Today's subject revolves around Calculus. Enjoy!
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The three programs listed here call another program as a subroutine. I use Prog 0 as a subroutine.
Prog 0
[insert f(x) here]
Example: Prog 0 contains X^2+4. The results gets stored in in Ans.
Sum
S = ∑( f(x), X = A to B)
"A"? -> A
"B"? -> B
A -> X
0 -> S
Lbl 1
Prog 0
Ans + S -> S
X + 1 -> X
X≤B => Goto 1
S
Numeric Derivative - Simple Approximation
f'(x) ≈ (f(x+h) - f(x-h))/(2h), h = tolerance (default to 10^-5)
The derivative is stored in the variable D.
"X0"? -> Z
Z+10^-5 -> X : Prog 0 : Ans -> A
Z-10^-5 -> X : Prog 0 : Ans -> B
(A-B)÷(2 10^-5) -> D
Definite Integral - Simpson's Rule
∫ f(x) dx ≈ h/3 * (y_a + ∑(4*y_odd + 2*y_even) + y_b)
where h=(b-a)/n (n is even)
The integral is stored in the variable I.
"A"? -> A
"B"? -> B
"N"? -> N
A -> X
Prog 0
Ans -> I
(B-A)÷N -> D
N÷2 -> K
Lbl 2
X+D -> X : Prog 0 : I + 4 Ans -> I
X+D -> X : Prog 0 : I + 2 Ans -> I
K - 1-> K
K≠0 => Goto 2
B -> X : Prog 0 : (I - Ans)D÷3 -> I
Eddie
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