Texas Instruments TI86 User Manual - Page 156

Solving a Differential Equation for a Specified Value, Using Graph Tools in DifEq Graphing Mode

Page 156 highlights

144 Chapter 10: Differential Equation Graphing To paste ' to the home screen, you can select it from the CHAR MISC menu or from the CATALOG. Due to TI-86 system requirements, you must express Q1(3) as Q'1(3) on the calculator. Solving a Differential Equation for a Specified Value On the home screen in DifEq graphing mode, you can solve a differential equation stored to a specified independent variable value or expression. The syntax is: Q'n(value). ♦ The equation must be stored to a DifEq equation variable (Q'1 through Q'9). ♦ The initial conditions must be defined. ♦ The result sometimes varies, depending on the axes settings. QuickZoom is available in DifEq graphing; panning is not (Chapter 6). Using Graph Tools in DifEq Graphing Mode The Free-Moving Cursor The free-moving cursor works in DifEq mode as it does in Func graphing. The cursor coordinate values for x and y are displayed, and the variables are updated. Tracing a Differential Equation To begin a trace, select TRACE from the GRAPH menu (6 / )). The trace cursor appears on the first equation at or near tPlot (or tMin, if t is an axis). The trace coordinates displayed at the bottom of the screen reflect the axes settings. For example, if x=t and y=Q1, then t and Q1 are displayed. If t is not an axis, three trace values are displayed. If t is an axis, only t and the variable designated as the y-axis are displayed. The trace cursor moves in increments or decrements of tStep. As you trace an equation, the coordinates are updated and displayed. If the cursor moves off the screen, the coordinate values displayed at the bottom of the screen continue to change appropriately.

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144
Chapter 10: Differential Equation Graphing
Solving a Differential Equation for a Specified Value
On the home screen in
DifEq
graphing mode, you can solve a
differential equation stored to a specified independent variable
value or expression. The syntax is:
Q'
n
(
value
)
.
The equation must be stored to a
DifEq
equation variable
(
Q'1
through
Q'9
).
The initial conditions must be defined.
The result sometimes varies, depending on the axes settings.
Using Graph Tools in DifEq Graphing Mode
The Free-Moving Cursor
The free-moving cursor works in
DifEq
mode as it does in
Func
graphing. The cursor
coordinate values for
x
and
y
are displayed, and the variables are updated.
Tracing a Differential Equation
To begin a trace, select
TRACE
from the
GRAPH
menu (
6
/
)
). The trace cursor
appears on the first equation at or near
tPlot
(or
tMin
, if
t
is an axis).
The trace coordinates displayed at the bottom of the screen reflect the axes settings. For
example, if
x=t
and
y=Q1
, then
t
and
Q1
are displayed. If
t
is not an axis, three trace values
are displayed. If
t
is an axis, only
t
and the variable designated as the y-axis are displayed.
The trace cursor moves in increments or decrements of
tStep
. As you trace an equation, the
coordinates are updated and displayed. If the cursor moves off the screen, the coordinate
values displayed at the bottom of the screen continue to change appropriately.
To paste
'
to the home
screen, you can select it from
the
CHAR
MISC
menu or from
the
CATALOG
.
Due to TI
-
86 system
requirements, you must
express
Q1(3)
as
Q'1(3)
on
the calculator.
QuickZoom is available in
DifEq
graphing; panning is
not (Chapter 6).