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Comparison of Definition of Several Fractional Derivatives
Yun Ouyang1, a and Wusheng Wang1, b* 1School of Mathematics and Statistics, Hechi University, Guangxi, Yizhou 546300, P. R. China
*The corresponding author
Keywords: Riemann-liouville fractional derivatives; Caputo's fractional derivative; Grunwald-letnikov fractional derivatives; Fractional integral.
Abstract. The idea of fractional derivatives was raised first by L'Hospital in 1695. The fractional
calculus and its mathematical consequences attracted many mathematicians such as Fourier, Euler,
Laplace. Various definitions of non-integer order integral or derivative was given by many
mathematicians. In this paper, firstly, we discuss the positive integer higher order derivative of a
function, and obtain general formula of high order derivative. Secondly, we introduce the definitions of
Gr\"unwald-Letnikov, Riemann-Liouville and Caputo. Finally, we point out the relationship between
these definitions. Caputo's integral definition and Gr\"unwald-Letnikov integral definition are
consistent with the Riemann-Liouville integral definition. When f has 1m order continuous
derivative and 1 mpm , Gr\"unwald-Letnikov positive non-integer order derivative definition is
consistent with the Riemann-Liouville positive non-integer order derivative definition.
Introduction
The idea of fractional derivatives was raised first by L'Hospital in 1695. The fractional calculus and its
mathematical consequences attracted many mathematicians such as Fourier, Euler, Laplace. Various
definitions of non-integer order integral or derivative was given by many mathematicians (see [1]). For
fractional derivative, the most popular definitions are Riemann- Liouville and Caputo definitions as
follows, respectively. Recently, the fractional calculus methods have become increasingly more
popular and successful in a large number of physical applications (see for example, [2, 3]). The
theoretical and experimental scientists observed that certain materials admit anomalous, fractional
behavior, as [4]. There are many systems which evolution is governed by some fractional differential
equations (for example, [5]). Fractional calculus is nowadays a broad and interesting field of very
active research (see [6-12]).
In this paper, firstly, we discuss the positive integer high order derivative of a function, and obtain
general formula of high order derivative. Secondly, we introduce the definitions of Gr\"
unwald-Letnikov, Riemann-Liouville and Caputo. Finally, we point out the relationship between these
definitions.
General Formula of High Order Derivative
Suppose that function )(tf has n order continuous differentiable derivative on ],[ ba . From the
definition of the derivative, we have
h
htftf
dt
dftf
h
)()(lim)('
0
, (1)
h
htftf
dt
fdtf
h
)(')('lim)(''
02
2
2016 6th International Conference on Education, Management and Computer Science (ICEMC 2016)
© 2016. The authors - Published by Atlantis Press 553
h
htfhtf
h
htftf
hh
)2()()()(1lim
0
20
)2()(2)(lim
h
htfhtftf
h
, (2)
By induction we can obtain
),()1(1
lim)(0
0
)( rhtfr
n
hdt
fdtf
n
r
r
nhn
nn
(3)
where n is a natural number,
!
)1()2)(1(
r
rnnnn
r
n
(4)
Let p be any arbitrary integer, define a new derivative (see [9,10])
0
0
lim ( 1)n
p p r
a th
rnh t a
pD f t h f t rh
r
, (5)
where nath /)( ,
!
)1()2)(1(
r
rpppp
r
p
. (6)
If ,0p let ,pq
!
)1()2)(1(
r
rqqqq
r
q
, (7)
then
r
q
r
rqqqq
r
pr)1(
!
)1()2)(1( , (8)
or,
r
q
r
pr)1( . (9)
From (5) and (9), we have
0
0
lim , 0, 0.n
q q
a th
rnh t a
qD f t h f t rh p q p
r
(10)
In particular, we have
10
0
1lim
n
a th
rnh t a
D f t h f t rhr
00
0
lim ,n t a t
ahrnh t a
h f t rh f t s ds f s ds
(11)
554
2 2 20 0
0 0
2lim lim 1
n n
a th h
r rnh t a nh t a
D f t h f t rh h r f t rhr
1
001
lim ,n t a t
ahrnh t a
h rh f t h rh sf t s ds t f d
(12)
3 3 30 0
0 0
3 1 2lim lim
2!
n n
a th h
r rnh t a nh t a
r rD f t h f t rh h f t rh
r
21 1
2
0 01 1
lim lim2! 2!
n n
h hr rnh t a nh t a
h hrh f t h rh rh f t h rh
22
0
1 1,
2! 3
t a t
as f t s ds t f d
(13)
Generally, for any positive integer p , define the p order derivative of a function )(tf
0 0
0 0
1 2 1lim lim
!
n np p p
a th h
r rnh t a nh t a
p p p p p rD f t h f t rh h f t rh
r r
00
1 2 1lim
( 1)!
np
hrnh t a
p p p p rh f t rh
p
11
01
lim1 !
np
hrnh t a
hrh f t h rh
p
2 12
0 01 0
lim lim2 2 !
n np p
h hr rnh t a nh t a
phrh f t h rh h f t rh
p
11
0
1 1.
1 !
t a t pp
as f t s ds t f d
p p
(14)
Since
2 11 .
-1
t pp p
a t a ta
dD f t t f d D f t
dt p
(15)
Then
1 2t t s
p p p
a t a t a ta a a
D f t D f s ds ds D f d
1 2 1 13
1 2 3 3 1 2 .pt t t t t tp
a t p pa a a a a adt dt D f t dt dt dt f t dt
(16) It implies that the derivative of negative integer p- order and the p-fold integral (2.21) of the
continuous function )(tf are equivalent.
Several Fractional Derivatives
Grunwald-Letnikov fractional derivative and integral definitions (see [9,10]): Let p be any arbitrary
positive real number, define p order derivative and p order integral of a continuous function )(tf :
0
0
lim -1)n
G p p ra t
hrnh t a
pD f t h f t rh
r
( , (17)
and
555
0
0
limn
G p pa t
hrnh t a
pD f t h f t rh
r
. (18)
Riemann-Liouville fractional derivative and integral definitions (see [9]): Let m be positive integer,
1 mpm , define Riemann-Liouville p order derivative and p order integral of a continuous
function )(tf : 1
( ) ( ) ( ) ,
mt
R p m p
a ta
dD f t t f d
dt
(19)
and
11( ) ( ) ( ) .( )
tR p p
a ta
D f t t f dp
(20)
Define Caputo's fractional derivative and integral definitions(see [9]): Suppose that )(tf
has m order
continuous derivative, define Caputo's p order derivative and p order integral: ( )
1
1 ( ),( 1 )
( ) ( )
mt
C p
a t p ma
fD d m p m
m p t
, (21)
and
11( ) ( ) ( ) .( )
tC p p
a ta
D f t t f dp
(22)
Comparison of the Definition of Riemann-Liouville, Caputo and Grunwald-Letnikov
Caputo's integral definition and Grunwald-Letnikov integral definition are consistent with the
Riemann-Liouville integral definition
11( )= ( )= ( ) ( ) ( ) .( )
tG p R p C p p
a a at t ta
D f t D f t D f t t f dp
(23)
When p is positive integer and ),,2,1(0)()( pkaf k , Caputo's derivative definition and
Grunwald-Letnikov derivative definition are consistent with the Riemann-Liouville derivative
definition. ( )= = ( )G p R p C p pa t a t a tD D D f t . (24)
If )(tf
has 1m order continuous derivative and 1 mpm , then
1
( ) ( ) ( )
mt
R p m p
a ta
dD f t t f d
dt
( )( 1)
0
( )( ) 1( ) ( )
( 1) ( 1)
k p km tm p m
ak
f a t at f d
p k p m
( ), 1.G pa tD f t m p m (25)
It implies that Grunwald-Letnikov positive non-integer order derivative definition is consistent with the
Riemann-Liouville positive non-integer order derivative definition.
Summary
Caputo's integral definition and Grunwald-Letnikov integral definition are consistent with the
Riemann-Liouville integral definition. When p is positive integer and ),,2,1(0)()( pkaf k ,
Caputo's derivative definition and Grunwald-Letnikov derivative definition are consistent with the
Riemann-Liouville derivative definition. It implies that Grunwald-Letnikov positive non-integer order
derivative definition is consistent with the Riemann-Liouville positive non-integer order derivative
definition.
556
Acknowledgements
This research was supported by National Natural Science Foundation of China (Project No. 11161018,
11561019) and Scientific Research Foundation of the Education Department of Guangxi Autonomous
Region of China (No. 201106LX599).
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