AN INTRODUCTION OF SUMUDU
TRANSFORM
S. Jeevitha
PG and Research Department of Mathematics
Marudhar Kesari Jain College For Women, Vaniyambadi, Tamil Nadu, India.
S. Komala
PG and Research Department of Mathematics
Marudhar Kesari Jain College For Women, Vaniyambadi, Tamil Nadu, India.
S. Silambarasi
PG and Research Department of Mathematics
Marudhar Kesari Jain College For Women, Vaniyambadi, Tamil Nadu, India.
S. Susitha
PG and Research Department of Mathematics
Marudhar Kesari Jain College For Women, Vaniyambadi, Tamil Nadu, India.
R.Vanitha
PG and Research Department of Mathematics
Marudhar Kesari Jain College For Women, Vaniyambadi, Tamil Nadu, India.
ABSTRACT
In this paper, we see the definition, some basic properties and fundamental properties
of Sumudu transform, relationships between Laplace and Sumudu transforms and Existence
of Sumudu transform.
KEYWORDS
Sumudu Transform, Gamma Function, Laplace Transform.
INTRODUCTION
The Sumudu transform is introduced by Watugula. Sumudu transform may be used
to solve problems without resorting to a new frequency domain .Due to its simple
formulation and consequent special and useful properties, the Sumudu transform has
already shown much promise. It is revealed here in and elsewhere that it can help to solve
intricate problems in engineering mathematics and applied sciences. However, despite the
potential presented by this new operator, only few theoretical investigations have appeared
in the literature, over a fifteen-year period. Most of the available transform theory books, if
not all, do not refer to the Sumudu transform. Even in relatively recent well known
comprehensive handbooks, such as Debnath and Poularikas, no mention of the Sumudu
transform can be found.
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SUMUDU TRANSFORM
Watugala introduced a new transform and named as Sumudu transform which is
defined by the following formula
๐น(๐ข) = ๐ฎ[๐(๐ก); ๐ข] =
1
๐ข
∫ ๐−(
1
๐ข
) ๐(๐ก)๐๐ก, ๐ข ∈ (−๐1, ๐2)
∞
0
BASIC SUMUDU TRANSFORM PROPERTIES
Sumudu transform for ๐ ∈ ๐ด:
๐บ(๐ข) = ๐ฎ[๐(๐ก)] = ∫ ๐(๐ข๐ก)๐−๐ก ๐๐ก, ๐ข ∈ (−๐1, ๐2) ∞
0
Duality with Laplace transforms:
๐บ(๐ข) =
๐น(1
⁄๐ข)
๐ข
, ๐น(๐ ) =
๐บ(1
⁄๐ )
๐
Linearity Property:
๐ฎ[๐๐(๐ก) + ๐๐(๐ก) = ๐๐ฎ[๐(๐ก)] + ๐๐ฎ[๐(๐ก)]]
Sumudu Transform of Function Derivatives:
๐บ1(๐ข) = ๐ฎ[๐,(๐ก)] =
๐บ(๐ข)−๐(0)
๐ข
=
๐บ(๐ข)
๐ข
−
๐(0)
๐ข
๐บ2(๐ข) = ๐ฎ[๐,,(๐ก)] =
๐บ(๐ข) − ๐(0)
๐ข2 =
๐บ(๐ข)
๐ข2 −
๐(0)
๐ข2 −
๐,(๐)
๐ข
๐บ๐(๐ข) = ๐ฎ[๐๐(๐ก)] =
๐บ(๐ข)
๐ข๐ −
๐(0)
๐ข๐ − ⋯ −
๐๐−1(๐)
๐ข
Sumudu transform of integral of a function:
๐ฎ [∫ ๐(๐)๐๐
1
0 ] = ๐ข๐บ(๐ข)
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SUMUDU TRANSFORM FUNDAMENTAL PROPERTIES
THE DISCRETE SUMUDU TRANSFORM
Over the set of functions
๐ด = {(๐(๐ก)|∃๐, ๐1,๐2 > 0, |๐(๐ก)| < ๐๐|๐ก|/๐๐ , ๐๐ ๐ก ∈ (−1)๐ × [0, ∞))}, (1)
the Sumudu transform is defined by
๐บ(๐ข) = ๐ฎ[๐(๐ก)] = ∫ ๐(๐ข๐ก)๐−๐ก ๐๐ก, ๐ข ∈ (−๐1, ๐2) ∞
0
(2)
Among others, the Sumudu transform was shown to have units preserving properties and
hence may be used to solve problems without resorting to the frequency domain. As will
be seen below, this is one of many strength points for this new transform, especially with
respect to applications in problems with
physical dimensions. In fact, the Sumudu transform which is itself linear, preserves linear
functions, and hence in particular does not change units (see for instance Watugala or
Belgacem et al).Theoretically, this point may perhaps best be illustrated as an implication
of this more global result.
THEOREM:1
The Sumudu transform amplifies the coefficients of the power series function,
๐(๐ก) = ฮฃ ๐๐๐ก๐ ∞
๐
=0 (1.1)
by sending it to the power series function,
๐บ(๐ข) = ฮฃ ๐! ๐๐๐ข๐ ∞
๐
=0 (1.2)
PROOF :
Let f (t) be in A. If ๐(๐ก) = ฮฃ ๐๐๐ก๐ ∞
๐
=0 in some interval I ⊂ R, then by Taylor’s
function expansion theorem,
๐(๐ก) = ฮฃ ๐(๐)(๐)
๐!
∞๐
=0 ๐ก๐
(1.3)
Therefore, by (2), and that of the gamma function ฮ , we have
๐ฎ[๐(๐ก)] = ∫ ฮฃ ๐(๐)(๐)
๐!
∞๐
=0 (๐ข๐ก)๐๐−๐ก ∞
0 ๐๐ก
= ฮฃ ๐(๐)(๐)
๐!
∞๐
=0 ๐ข๐ ∫ ๐ก๐ ∞
0 ๐−๐ก ๐๐ก
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= ฮฃ ๐(๐)(๐)
๐!
∞๐
=0 ๐ข๐ ฮ(n+1)
= ฮฃ ๐(๐)(0)๐ข๐ ∞
๐
=0 (1.4)
Consequently, it is perhaps worth noting that since
๐ฎ[(1 + ๐ก)๐] = ๐ฎ ฮฃ ๐ถ๐
๐๐ก๐ ๐๐
=0
= ๐ฎ ฮฃ ๐!
๐!(๐−๐)!
๐๐
=0 ๐ข๐
๐ฎ[(1 + ๐ก)๐] = ฮฃ
๐!
(๐−๐)!
๐ ๐=
0
๐ข๐
=ฮฃ ๐๐
๐๐ข๐ ๐๐
=0 (1.5)
the Sumudu transform sends combinations, ๐ถ๐
๐ into permutations, ๐๐
๐, and hence may
seem to incur more order into discrete systems.
Also, a requirement that ๐ฎ[๐(๐ก)] converges, in an interval containing u=0, is provided by
the following conditions when satisfied, namely, that
(๐)๐(๐)(0) → 0 ๐๐ ๐ → ∞,
(๐๐) lim
๐→∞
|
๐(๐+1)(0)
๐(๐)(0)
๐ข| < 1 (1.6)
This means that the convergence radius r of ๐ฎ[๐(๐ก)] depends on the sequence
๐(๐)(0), since
๐ = lim
๐→∞
|
๐(๐+1)(0)
๐(๐)(0)
| (1.7)
Clearly, the Sumudu transform may be used as a signal processing or a detection
tool,especially in situations where the original signal has a decreasing power tail .
However, care must be taken, especially if the power series is not highly decaying. This
next example may instructively illustrate the stated concern. For instance, consider the
function
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๐(๐ก) = {
๐ผ๐ (๐ก + 1) ๐๐ ๐ก ∈ (−1,1]
๐ ๐๐กโ๐๐๐ค๐๐ ๐
(1.8)
Since ๐(๐ก) = ฮฃ (−1)๐−1 ∞
๐
=1
๐ก๐
⁄๐ the expect for u=0
๐ฎ[๐(๐ก)] = ฮฃ (−1)๐−1(๐ − 1)! ๐ข๐ ∞
๐
=1 (1.9)
Diverges throught , because its convergens radius
๐ = lim
๐→∞
|
(−1)๐−1(๐−1)!
(−1)๐๐!
|
lim
๐→∞
1
๐
= 0 (1.10)
RELATION BETWEEN SUMUDU AND LAPLACE TRANSFORM
In our study, we use the following convolution notation: double convolution
between two continuous functions F (x, y) and G(x, y) given by
๐น1(๐ฅ, ๐ฆ) ∗∗ ๐น2(๐ฅ, ๐ฆ) = ∫ ∫ ๐น1(๐ฅ − ๐1, ๐ฆ − ๐2)๐น2(๐1, ๐2)๐๐1๐๐2
๐ฅ
0
๐ฆ
0
The single Sumudu transform is defined over the set of the functions
๐ด = {(๐(๐ก)|∃๐, ๐1,๐2 > 0, |๐(๐ก)| < ๐๐|๐ก|/๐๐ , ๐๐ ๐ก ∈ (−1)๐ × [0, ∞))}
by ๐บ(๐ข) = ๐ฎ[๐(๐ก)] = ∫ ๐(๐ข๐ก)๐−๐ก ๐๐ก, ๐ข ∈ (−๐1, ๐2) ∞
0
A sufficient condition for the existence of the Sumudu transform of a
function f is of exponential order, that is, there exist real constants
M > 0, ๐พ1, and ๐พ2 , such that |๐(๐ก, ๐ฅ)| ≤ ๐๐
๐ก
๐พ1
+
๐ฅ
๐พ2
EXISTENCE OF THE SUMUDU TRANSFORM
THEOREM:2
If f is of exponential order, then its Sumudu transform ๐ฎ[๐(๐ก, ๐ฅ)] = ๐น(๐ฃ, ๐ข)exists and is
given by
๐น(๐ฃ, ๐ข) = ∫ ∫ ๐−
๐ก
๐ฃ
−
๐ฅ
๐ข๐(๐ก, ๐ฅ)
∞
0
∞
0
๐๐ก๐๐ฅ
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where
1
๐ข
=
1
ษณ
+
๐
๐
,
1
๐ฃ
=
1
๐
+
๐
๐
The defining integral for F exists at points
1
๐ข
+
1
๐ฃ
=
1
ษณ
+
1
๐
+
๐
๐
+
๐
๐
in the right half plane
1
ษณ
+
1
๐
>
1
๐พ1
+
1
๐พ2
.
PROOF:
Using
1
๐ข
=
1
ษณ
+
๐
๐
๐๐๐
1
๐ฃ
=
1
๐
+
๐
๐
We can express ๐น(๐ฃ, ๐ข) as
๐น(๐ฃ, ๐ข) = ∫ ∫ ๐(๐ก, ๐ฅ)๐๐๐ (
๐ก
๐
+
๐ฅ
๐
)๐
−
๐กษณ
−
๐ฅ๐
∞
0
∞
0
๐๐ก๐๐ฅ
−๐ ∫ ∫ ๐(๐ก, ๐ฅ)๐ ๐๐(
๐ก
๐
+
๐ฅ
๐
)๐
−
๐ก
ษณ
−
๐ฅ
๐
∞
0
∞
0 ๐๐ก๐๐ฅ
Then for values of 1
ษณ
+
1
๐
>
1
๐พ1
+
1
๐พ2
we have
∫ ∫ |๐(๐ก, ๐ฅ)| |๐๐๐ (
๐ก
๐
+
๐ฅ
๐
)| ๐
−
๐กษณ
−
๐ฅ๐
∞
0
∞
0
๐๐ก๐๐ฅ ≤ ๐ ∫ ∫ ๐
(
1
๐พ1
−
1
ษณ
)๐ก+(
1
๐พ2
−
1
๐
)๐ฅ
∞
0
∞
0
๐๐ก๐๐ฅ
≤ ๐ (
ษณ๐พ1
ษณ−๐พ1
) (
ษณ ๐พ2
๐− ๐พ2
)
and
∫ ∫ |๐(๐ก, ๐ฅ)| |๐ ๐๐(
๐ก
๐
+
๐ฅ
๐
)| ๐
−
๐กษณ
−
๐ฅ๐
∞
0
∞
0
๐๐ก๐๐ฅ ≤ ๐ ∫ ∫ ๐
(
1
๐พ1
−
1
ษณ
)๐ก+(
1
๐พ2
−
1
๐
)๐ฅ
∞
0
∞
0
๐๐ก๐๐ฅ
≤ ๐ (
ษณ๐พ1
ษณ−๐พ1
) (
ษณ ๐พ2
๐− ๐พ2
)
which imply that the integrals defining the real and imaginary parts of F exist for value of
๐ ๐ (
1
๐ข
+ 1
๐
) > 1
๐พ1
+
1
๐พ2
, and this completes the proof.
Thus, we note that for a function f, the sufficient conditions for the existence of the
Sumudu transform are to be piecewise continuous and of exponential order.
We also note that the double Sumudu transform of function f(t, x) is defind by
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๐น(๐ฃ, ๐ข) = ๐ฎ2[๐(๐ก, ๐ฅ); (๐ฃ, ๐ข)] =
1
๐ข๐ฃ
∫ ∫ ๐−(
๐ก
๐ฃ
+
๐ฅ
๐ข
)๐(๐ก, ๐ฅ)
∞
0
∞
0
๐๐ก๐๐ฅ
where, ๐ 2 indicates double Sumudu transform and ๐(๐ก, ๐ฅ ) is a function which can be
expressed as a convergent infinite series. Now, it is well known that the derivative of
convolution for two functions ๐ and ๐ is given by
๐
๐๐ฅ
(๐ ∗ ๐)(๐ฅ) =
๐
๐๐ฅ
๐(๐ฅ) ∗ ๐(๐ฅ)๐๐ ๐(๐ฅ) ∗
๐
๐๐ฅ
๐(๐ฅ)
and it can be easily proved that Sumudu transform is
๐ฎ [
๐
๐๐ฅ
(๐ ∗ ๐)(๐ฅ); ๐ฃ] = ๐ข๐ฎ [
๐
๐๐ฅ
๐(๐ฅ); ๐ข] ๐ฎ[๐(๐ฅ); ๐ข] or
= ๐ข๐ฎ[๐(๐ฅ); ๐ข]๐ฎ [
๐
๐๐ฅ
๐(๐ฅ); ๐ข].
The double Sumudu and double Laplace transforms have strong relationships that may be
expressed either as
(๐ผ) ๐ข๐ฃ๐น(๐ข, ๐ฃ) = £2 (๐(๐ฅ, ๐ฆ); (
1
๐ข
,
1
๐ฃ
))
Or (๐ผ๐ผ) ๐๐ ๐น(๐, ๐ ) = £2 (๐(๐ฅ, ๐ฆ); (
1
๐
,
1
๐
))
where £2 represents the operation of double Laplace transform. In particular, the double
Sumudu and double Laplace transforms interchange the image of sin(x + t) and cos(x + t).
It turns out that
๐ 2[sin(๐ฅ + ๐ก)] = £2[cos(๐ฅ + ๐ก) =
๐ข + ๐ฃ
(1 + ๐ข)2(1 + ๐ฃ)2
And
๐ 2[cos(๐ฅ + ๐ก)] = £2[sin(๐ฅ + ๐ก) =
1
(1 + ๐ข)2(1 + ๐ฃ)2
REFERENCE:
1. G. K. Watugala, Sumudu Transform: a new integral transform to solve differential
equations and control engineering problems, Internat. J. Math. Ed. Sci.Tech. 24 (1993) 35-
43.
2.G. K. Watugala, The Sumudu transform for functions of two variables, Math.
© 2021 JETIR July 2021, Volume 8, Issue 7 www.jetir.org (ISSN-2349-5162)
JETIR2107602 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org e778
Engrg. Indust. 8 (2002) 293-302.
3. M.A.Asiru,Sumudu transform and the solution of integral equations of onvolution type,
International Journal of Mathematical Education in Science and Technology 32 (2001),
no. 6, 906–910.
4. Further properties of the Sumudu transform and its applications, International Journal of
Mathematical Education in Science and Technology 33 (2002), no.3, 441–449.
5. Classroom note: application of the Sumudu transform to discrete dynamic systems,
International Journal of Mathematical Education in Science and Technology 34 (2003),
no. 6,944–949.