7000G Retro Month - June 12 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 Graphics. Enjoy!
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Get a emulator or graphing calculator to see the results.
Quadratic Fit by Two Roots
Given two roots A and B, the program generates a quadratic equation and it's graph. The program assumes that the vertex is a minimum.
Y = (X - A) (X - B)
"ROOT1" -> A
"ROOT2" -> B
"Y = X^2 - " /I
A+B /I
"X + " /I
AB /I
Cls
Graph Y=(X-A)(X-B)
Polar Plotting (Self Contained)
I usually use Radians (Mode 5 for fx-7000G, fx-7500G, fx-6300G) angle mode when it comes to graphics and calculus. To set/change each equation, you will need to edit the program here. I state the equation to be in the form r(T) where T = θ.
On the Rec command, x is stored to I and y is stored to J. (specific to fx-7000G, fx-7500G, fx-6300G)
"POLAR R(T)"
Rad
"RMIN"? -> A
"RMAX"? -> B
"N"? -> N
(B-A)÷N -> H
A-H -> T
Cls
Lbl 1
T+H -> T
[insert r(T) here]
Rec(Ans, T)
Plot I,J
T<B => Goto 1
Cubic Bezier Curve
This program plots a cubic Bezier curve with the following variables:
(x0, y0): A = A[0], B = A[1] (exact fit)
(x1, y1): C = A[2], D = A[3]
(x2, y2): E = A[4], F = A[5]
(x3, y3): G = A[6], H = A[7] (exact fit)
Cls
0 -> I
"CUBIC BEZIER"
Lbl 1
"X"? -> A[ I ]
Isz I
"Y"? -> A[ I ]
Isz I
I < 8 => Goto 1
0 -> T
Lbl 2
A(1-T)^3 + 3C(1-T)^2 T + 3E(1-T) T^2 + GT^3 -> X
B(1-T)^3 + 3D(1-T)^2 T + 3F(1-T) T^2 + HT^3 -> Y
Plot X,Y
T+.02 -> T
T<1 => Goto 2
Press [ G<>T ] to see the graph.
Polygon Drawing
The programs allow the user to draw many lines in a row by connecting points. The original point are stored in variables E and F. To complete the polygon, use (E, F) as the final point.
The prompt MORE: enter 0 to stop, anything else to continue connecting points
Cls
"X0"? -> A : A -> E
"Y0"? -> B : B -> F
Plot A,B
Lbl 1
"ORIG (E,F)"
"NEXT X"? -> C
"NEXT Y"? -> D
0 -> T
Lbl 2
(1-T)A+CT -> X
(1-T)B+DT -> Y
Plot X,Y
T+.02->T
T<1 => Goto 2
C -> A : D -> B
"MORE"? -> M
M≠0 => Goto 1
Drawing an Ellipse
This program draws an ellipse.
"ELLIPSE"
"X RADIUS"? -> A
"Y RADIUS"? -> B
Rad
Cls
Range -A-.5,A+.5,(2A+1)÷20,-B-.5,B+.5,(2B+1)÷20
0 -> T
Lbl 1
Plot A cos T, B sin T
T+2π÷64 -> T
T<2π => Goto 1
Press [ G<>T ] to see the graph.
Eddie
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