Texas Instruments TITANIUM TI-89 - Manual (Page 439)

Differential Equation Graphing 439
Example Comparison of RK and Euler Example Comparison of RK and Euler Example Comparison of RK and Euler Example Comparison of RK and Euler
Consider a logistic growth model dP/dt = .001
ù
P
ù
(100 N P) , with the initial condition P(0) =
10 . Use the BldData instruction to compare the graphing points calculated by the RK and
Euler solution methods. Then plot those points along with a graph of the equation’s exact
solution.
Example Example Example Example
13. Return to the Graph screen, which
displays a curve for each pair of initial
conditions.
14. Press … to trace. Then press
3
¸ to
see the number of foxes ( xc ) and rabbits
( yc ) at t=3 .
Because t0=0 and tmax=10 , you can trace
in the range 0  t  10.
Note: Use C and D to move the trace
cursor from one initial condition curve to
another.
1. Press 3 and set
Graph=DIFF
EQUATIONS .