Solution 2.9.5.10
Applying the Laplace transform yields
s
2
Y (s) ; sy(0) ; y
[1]
(0) + 2[sY (s) ; y(0)]+ 10Y (s)=0:
Rearranging yields
(s
2
+2s + 10)Y(s) = sy(0) + 2y(0)+ y
[1]
(0)
=
s
2
y(0) + s[y
[1]
(0)+ 8y(0)]+ 15
(s +1; j3)(s+1+j3)
:
For the given initial conditions we then have
Y (s) =
3
(s +1; j3)(s+1+j3)
=
M
s +1; j3
+
M
s +1+j3
:
M = (s +1; j3)Y(s) j
s=;1+j3
=
3
(s +1+j3)
j
s=;1+j3
= ;j=2
= 0:5
6
;=2
Then
y(t)=[e
;t
cos(3t ; =2)]1(t):
1