A Runge-Kutta-4 Solution grapher for Differential Equations on the TI-82/83
-- 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
= xy2/5, that have a specific initial condition, such
as y(1)=4. It uses the Runge-Kutta 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.
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 stopping-value 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.
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