Laplace transforms
Definition of Laplace Transform
First Shifting Theorem
Inverse Laplace Transform
Convolution Theorem
Application to Differential Equations
Laplace Transform of Periodic Functions
Unit Step Function
Second Shifting Theorem
Dirac Delta Function
2. Topics
Definition of Laplace Transform
Linearity of the Laplace Transform
Laplace Transform of some Elementary Functions
First Shifting Theorem
Inverse Laplace Transform
Differentiation & Integration of Laplace Transform
Evaluation of Integrals By Laplace Transform
Convolution Theorem
Application to Differential Equations
Laplace Transform of Periodic Functions
Unit Step Function
Second Shifting Theorem
Dirac Delta Function
3. Definition of Laplace Transform
Let f(t) be a given function of t defined for all
then the Laplace Transform of f(t) denoted by L{f(t)}
or or F(s) or is defined as
provided the integral exists, where s is a parameter real
or complex.
0t
)(sf )(s
dttfessFsftfL st
)()()()()}({
0
4. Linearity of the Laplace Transform
If L{f(t)}= and then for any
constants a and b
)(sf )()]([ sgtgL
)]([)]([)]()([ tgbLtfaLtbgtafL
)]([)]([)}()({
)()(
)]()([)}()({
Definition-By:Proof
00
0
tgbLtfaLtbgtafL
dttgebdttfea
dttbgtafetbgtafL
stst
st
5. Laplace Transform of some Elementary
Functions
asif
a-s
1
)(
e.)e(
Definition-By:Proof
a-s
1
)L(e(2)
)0(,
s
1
1.)1(
Definition-By:Proof
s
1
L(1)(1)
0
)(
0
)(
0
atat
at
00
as
e
dtedteL
s
s
e
dteL
tas
tasst
st
st
8. n!1n0,1,2...n
n!
)(or
0,n-1n,
1
)(
1
ust,.)-L(:Proof
n!
or
1
)()8(
1
0
1
1
0
1)1(
1
0
0
11
n
n
nx
n
n
nu
n
n
u
nstn
nn
n
S
tL
ndxxe
S
n
tL
duue
S
s
du
s
u
e
puttingdttet
SS
n
tL