A RungeKutta4 Solution grapher for Differential Equations on the TI82/83
 a program 
This is for solving differential equations of the form dy/dx
= (and expression in terms of x and y), such as dy/dx
= xy^{2}/5, that have a specific initial condition, such
as y(1)=4. It uses the RungeKutta method of order 4. The solution
curve is graphed, and the final value for y can be displayed.
The program is available in two formats.
A binary version that you can load directly into
the graphlink program and download to your calculator. NOTE: If
you have trouble downloading this, try holding the shift button on your
keyboard when you click on the link.
A screen shot for those typing in by hand.
Instructions:

Store the expression for dy/dx in Y1 on the
[Y=] screen. (In the example above, Y1=XY^2/5)

Set the [WINDOW] as you desire.

Run the program RK4

When asked for input:

Input the initial value for x as X START, the initial
value for y as Y START.

Give a stoppingvalue of x as FINAL X

Give the desired number of steps as STEPS (note: more steps
means better accuracy and slower program execution).

The solution curve is then graphed by the program

After the program stops, you can type X [ENTER][ALPHA]Y[ENTER] to
see the final values of x and y.
Last Modified December 8, 1998.
Prof.
Janeba's Home Page  Send comments or questions to: mjanebawillamette.edu
Department
of Mathematics  Willamette
University Home Page