HP 50g HP 50g_user's manual_English_HDPSG49AEM8.pdf - Page 145

X^3-4*X^2-11*X+30, This result is

Page 145 highlights

• the right-hand side of the ODE • the characteristic equation of the ODE Both of these inputs must be given in terms of the default independent variable for the calculator's CAS (typically X). The output from the function is the general solution of the ODE. The examples below are shown in the RPN mode: Example 1 - To solve the homogeneous ODE d3y/dx3-4⋅(d2y/dx2)-11⋅(dy/dx)+30⋅y = 0. Enter: 0 ` 'X^3-4*X^2-11*X+30'` LDEC µ The solution is (figure put together from EQW screenshots): where cC0, cC1, and cC2 are constants of integration. This result is equivalent to y = K1⋅e-3x + K2⋅e5x + K3⋅e2x. Example 2 - Using the function LDEC, solve the non-homogeneous ODE: d3y/dx3-4⋅(d2y/dx2)-11⋅(dy/dx)+30⋅y = x2. Enter: 'X^2' ` 'X^3-4*X^2-11*X+30'` LDEC µ The solution is: which is equivalent to y = K1⋅e-3x + K2⋅e5x + K3⋅e2x + (450⋅x2+330⋅x+241)/13500. Page 14-2

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Page 14-2
the right-hand side of the ODE
the characteristic equation of the ODE
Both of these inputs must be given in terms of the default independent
variable for the calculator’s CAS (typically X).
The output from the function
is the general solution of the ODE.
The examples below are shown in the
RPN mode:
Example 1
– To solve the homogeneous ODE
d
3
y/dx
3
-4
(d
2
y/dx
2
)-11
(dy/dx)+30
y = 0.
Enter:
0
`
'X^3-4*X^2-11*X+30'
`
LDEC
μ
The solution is (figure put together from EQW screenshots):
where cC0, cC1, and cC2 are constants of integration.
This result is
equivalent to
y = K
1
e
–3x
+ K
2
e
5x
+ K
3
e
2x
.
Example 2
– Using the function LDEC, solve the non-homogeneous ODE:
d
3
y/dx
3
-4
(d
2
y/dx
2
)-11
(dy/dx)+30
y = x
2
.
Enter:
'X^2'
`
'X^3-4*X^2-11*X+30'
`
LDEC
μ
The solution is:
which is equivalent to
y = K
1
e
–3x
+ K
2
e
5x
+ K
3
e
2x
+ (450
x
2
+330
x+241)/13500.