Texas Instruments TI-89 Voyage 200, User Manual

Page: 419 / 1008

Differential Equation Graphing 419
Standard values (set when you select
6:ZoomStd
from the
„
Zoom
toolbar menu) are:
You may need to change the standard values for the t variables to ensure that sufficient
points are plotted.
The fldpic System Variable The fldpic System Variable The fldpic System Variable The fldpic System Variable
When a slope or direction field is drawn, a picture of the field is stored automatically to a
system variable named
fldpic
. If you perform an operation that regraphs the plotted
equations but does not affect the field, the TI-89 Titanium reuses the picture in
fldpic
instead of having to redraw the field. This can speed up the regraphing time significantly.
fldpic
is deleted automatically when you exit the differential equation graphing mode or
when you display a graph with
Fields = FLDOFF
.
Exploring a Graph Exploring a Graph Exploring a Graph Exploring a Graph
As in function graphing, you can explore a graph by using the following tools. Any
displayed coordinates are shown in rectangular or polar form as set in the graph format.
t0 = 0.
tmax = 10.
tstep = .1
tplot = 0.
xmin = L 1.
xmax = 10.
xscl = 1.
ymin = L 10.
ymax = 10.
yscl = 1.
ncurves = 0.
diftol = .001
Estep = 1.
fldres = 14.
dtime = 0.
Tool For Differential Equation Graphs:
Free-Moving
Cursor Works just as it does for function graphs.