Solution 2.9.5.11
Applying the Laplace transform yields
s
2
Y (s) ; sy(0); y
[1]
(0)+ 4[sY (s); y(0)]+ 4Y (s)=0:
Rearranging yields
(s
2
+4s +4)Y (s)=sy(0)+ 4y(0)+ y
[1]
(0);;
or
Y (s)=
sy(0)+ 4y(0)+ y
[1]
(0)
(s +2)
2
For the given initial conditions we then have
Y (s) =
2s +5
(s +2)
2
=
A
s +2
+
B
(s +2)
2
:
A =
d
ds
h
(s +2)
2
Y (s)
i
j
s=;2
= [(d=ds)(2s+5)]j
s=;2
= 2:
B =
h
(s +2)
2
Y (s)
i
j
s=;2
= [(2s+ 5)] j
s=;2
= 1
Then,
y(t)=[2e
;2t
+ te
;2t
]1(t):
1