Solution 2.9.5.6
Applying the Laplace transform yields
s
2
Y (s); sy(0); y
[1]
(0);4[sY (s); y(0)]+ 5Y (s)=0:
Rearranging yields
(s
2
;4s +5)Y (s)=sy(0); 4y(0)+ y
[1]
(0);;
or
Y (s)=
sy(0); 4y(0)+ y
[1]
(0)
(s; 2; j)(s;2+j)
:
For the given initial conditions we then have
Y (s) =
s; 1
(s;2; j)(s;2+j)
=
M
s; 2;j
+
M
(s;2+j)
:
M = (s;2+j)Y (s) j
s=2+j
=
s;1
(s ;2+j)
s=2+j
=
1+j
j2
= 0:5;j0:5
=
q
(2)=2
6
; 45
=
p
2=2
6
;=4r.
y(t)=[
p
2e
2t
cos(t;=4)]1(t)
1