HP Prime: Slopefield (Differential Equations)

HP Prime:  Slopefield (Differential Equations)

Here is a program that graphs the slopefield of a differential equation in the form dy/dx = f(x,y).  This program is adopted from Alan Ziv’s SLPFIELD program, which Ziv programmed for the Casio fx-9850G.  The link to the original program is here:  http://www.spiderpixel.co.uk/caspro/progs/9x50g/slopefield.txt

For the HP Prime version, enter dy/dx in quotes, and use capital letters X and Y.  I recommend that you are in the Function app for this.  The window should be set up before running SLOPEFIELD.

Program SLOPEFIELD

EXPORT SLOPEFIELD(dxy)

BEGIN

// dxy: dx/dy = f′(x,y)

// Adopted from Alan Ziv -

// Casio

// dxy is in quotes

LOCAL X,Y,C,D,J,K,G,H;

LOCAL F,xa,xb,ya,yb,E;

// Use the Function App

RECT();

C:=(Ymax-Ymin)/220;

D:=(Xmax-Xmin)/320;

FOR J FROM 0 TO 50 DO

E:=Xmin+(8*J+3)*D;

FOR K FROM 0 TO 27 DO

F:=Ymin+(8*K+3)*C;

X:=E;

Y:=F;

G:=EXPR(dxy);

H:=2*D;

IF ABS(G)>C/D THEN

H:=2*C/ABS(G);

END;

IF 2*H>D THEN

xa:=E-H; ya:=G*(xa-E)+F;

xb:=E+H; yb:=G*(xb-E)+F;

LINE(xa,ya,xb,yb);

ELSE

LINE(E,F+2*C,E,F-2*C);

END;

END;

END;

// Draw Axis

LINE(Xmin,0,Xmax,0,#C0C0C0h);

LINE(0,Ymin,0,Ymax,#C0C0C0h);

WAIT(0);

END;

 Examples:

dy/dx = X*^Y^2 + 3*X

 

dy/dx = Y*SIN(X)

This blog is property of Edward Shore.  2015

Eddie

Graphing Calculator Programming Languages Comparison: TI 84 Plus vs Casio Prizm

This is a short comparison between the programming languages of the Texas Instruments TI-84+ and the Casio Prizm. For each category, I will list the different syntaxes required.

If you find a program that you like that is programmed on a calculator you don't have, no fear! This guide can be served as a translation guide. For more details, consult the manual or search for detailed tutorials.

Hope this helps,

Eddie

Notes:

The commands for the TI-84+ also covers the TI-84+ Silver Edition, TI-83+ Silver Edition, TI-83+, and most likely the TI-82 and the upcoming TI-84+ Plus C Silver Edition (84+ with a color screen). The TI-84+ family carries a program memory of about 24,000 bytes, 28,000 for the TI-82.

The commands for the Casio Prizm (Model fx-CG 10/20) also apply to the fx-9860g (all versions), fx-9750g, and (most likely) fx-9850g. The Casio family carriers about 60,000-62,000 bytes of program memory, except the 9850g (32,000 bytes).

Keystrokes may vary.

Arguments in each command are in italics.

Here we go:

Numerical Derivative

TI-84+: MATH, 8
nDeriv(f(variable),var,value)

Casio Prizm: OPTN, F4, F2
d/dx(f(X),value)
The variable is always X.

Definite Integral

TI-84+: MATH, 9
fnInt(f(var), var, lower limit, upper limit)

Casio Prizm: OPTN, F4, F4
∫(f(X),lower limit,upper limit)
The variable is always X.

Solve

TI-84+: Catalog or MATH, B in programming mode
solve(expression,variable to be solved for,guess, range*)
expression is set to be equal to 0
range is a two element list {low, high}, and is an optional argument.

Casio Prizm:

There are two commands.

Solve f(X)=0 for X: OPTN, F4, F1
Solve(f(X),guess,low,high)

Solve an equation in any variable: OPTN, F4, F5
SolveN(equation,variable to be solved for,low,high)

Sums

TI-84+: MATH, 0
Σ(f(var),var,start value,end value)

Casio Prizm: OPTN, F4, F6, F3
Σ(f(var),var,start value,end value)

Asking for Input

TI-84+:
Input "prompt string", var

Casio Prizm:
"prompt string"? → var

Displaying Results

TI-84+:
Disp var or string
You can add other lines, using commas to separate them.

Pause var
Pause allows the user to scroll the variable's value.

Casio Prizm:
var or string ◢
The ◢ is the right triangle symbol, which acts like a pause command.

If Then Else

TI-84+:
If test expression
Then
do this if test is true
Else
do this if test is false
End

Casio Prizm:
If test expression
Then
do this if test is true
Else
do this if test is false
EndIf

Shortcut: Jump Command
test condition ⇒ 1 command if test is true : skip to here if the test is false

For Loop

TI-84+:
For(counter var,start value,end value,step size*)
commands
End

step size can be positive or negative, and is optional

Casio Prizm:
For start value → var To end value Step step size*
commands
End

step size can be positive or negative, and is optional

While Loop

TI-84+:
While this test condition is true
do these commands
End

Casio Prizm:
While this test condition is true
do these commands
WhileEnd

Do Until Loop

TI-84+:
Repeat until this condition becomes true
these commands
End

Casio Prizm:
Do
these commands
LpWhile this condition remains false

List and Matrix Element Calls

TI-84+:
Lists:
L#(element number)
#: 1 through 6 or custom name

Matrix:
[[#]](row,column)
#: A through J

Casio Prizm:
Lists:
List #[element number]
#: 1 through 26 or custom name

Matrix:
Mat #[row,column]
#: 1 through 26

Giving the user a menu of options

TI-84+:
Menu("title string", "choice 1",label name...)
Up to 7 menu items

Casio Prizm:
Menu "title string", "choice 1", label name...
Up to 9 menu items

Decrementing and Incrementing Variables by 1

TI-84+:
IS>(var,target value)
do if var + 1 ≤ target value
skip to here if var + 1 > target value

DS<(var,target value)
do if var - 1 ≥ target value
skip to here if var - 1 < target value

Casio Prizm:
ISZ var
do if var + 1 ≠ 0
skip to here if var + 1 = 0

DSZ var
do if var - 1 ≠ 0
skip to here if var - 1 = 0



This blog is property of Edward Shore, 2012.