Texas Instruments TI-89 Voyage 200, Руководство пользователя

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Differential Equation Graphing 428
Example
Example Example
Example
1. Press
3
and set
Graph=DIFF EQUATIONS
.
2. Define a system of equations for the 2nd-
order equation.
Rewrite the equation and make the
necessary substitutions.
3. In the Y= Editor (
8 #
), enter the
system of equations.
4. Enter the initial conditions:
yi1=0
and
yi2=1
Note: t0
is the time at which the initial
conditions occur. It is also the first t
evaluated for the graph. By default,
t0=0
.
5. Press:
,
9
— or —
@ 8
Í
and set
Axes = ON
,
Labels =
OFF
,
Solution Method = RK
, and
Fields = DIRFLD
.
Important:
For 2nd-order equations, you
must set
Fields=DIRFLD
or
FLDOFF
.
y'' + y = 0
y'' =
L
y
y'' = L y1
y2' =
L
y1
yi1 is the initial
condition for y(0).
yi2 is the initial
condition for y'(0).