Texas Instruments TI-89 Titanium User Manual page 421

Example
1. Press 3 and set
2. Define a system of equations for the 3rd-
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:
, , and
yi1=0 yi2=1
is the time at which the initial
Note: t0
conditions occur. By default,
5. Be sure that only
to deselect any other equations.
Differential Equation Graphing
Graph=DIFF EQUATIONS
yi3=1
.
t0=0
is selected. Use †
y1'
.
y''' + 2y'' + 2y' + y =
sin(x)
y''' = sin(x) N 2y'' N 2y'
N y
y''' = sin(t) N 2y'' N 2y'
y
N
y''' = sin(t) N 2y3 N 2y2
y1
N
y3' = sin(t) N 2y3 N 2y2
y1
N
Important: The
solution to the y1'
equation is the
solution to the 3rd-
order equation.
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