2.9.5.1
Applying the Laplace transform yields
s
2
Y (s);sy(0);y
[1]
(0)+ sY (s);y(0);2Y (s)=0:
Rearranging yields
(s
2
+ s;2)Y (s)=sy(0)+ y(0)+ y
[1]
(0);;
or
Y (s)=
sy(0) + y(0)+ y
[1]
(0)
(s
2
+ s;2)
For the given initial conditions we then have
Y (s) =
3
(s + 2)(s;1)
=
A
s +2
+
B
s;1
:
A = (s +2)Y (s)
s=;2
=
3(s +2)
(s +2)(s;1)
s=;2
=
3
(s;1)
s=;2
= ;1
B = (s;1)Y (s)
s=1
=
3(s;1)
(s +2)(s;1)
s=1
=
3
(s +2)
s=1
= 1
Then
f(t)=[e
t
;e
;2t
]1(t):
1