Texas Instruments TI-89 Titanium User Manual page 412

Selecting an Initial Condition Interactively from the Graph Screen
When a differential equation is graphed (regardless of whether a solution curve is
displayed), you can select a point on the Graph screen and use it as an initial condition.
If Fields = Do this:
SLPFLD Press:
@
– or –
DIRFLD
Specify an initial condition. Either:
•
•
A circle marks the initial condition and the solution curve is
drawn.
Differential Equation Graphing
2 Š
Move the cursor to the applicable point and press
– or –
For each of the two coordinates, type a value and press
¸
.
- For SLPFLD (1st-order only), enter values for
y(t0)
.
- For DIRFLD (2nd-order or system of two 1st-order
equations only), enter values for both
conditions, where
or Window Editor.
y(t0)
t0
is the value set in the Y= Editor
¸
.
t0
and
initial
409