symmetry
S S
Article
Coefficient Bounds for Certain Classes of Analytic Functions
Associated with Faber Polynomial
Adel A. Attiya
1,2
, Abdel Moneim Lashin
2,3
, Ekram E. Ali
1,4
and Praveen Agarwal
5,6,7,8,
*
Citation: Attiya, A.A.; Lashin, A.M.;
Ali, E.E.; Agarwal, P. Coefficient
Bounds for Certain Classes of
Analytic Functions Associated with
Faber Polynomial. Symmetry 2021, 13,
302. https://doi.org/10.3390/
sym13020302
Academic Editor: Dmitriy V. Dolgy
Received: 31 October 2020
Accepted: 30 January 2021
Published: 10 February 2021
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4.0/).
1
Department of Mathematics, College of Science, University of Ha’il, Ha’il 81451, Saudi Arabia;
aattiy@mans.edu.eg (A.A.A.); ekram_008eg@yahoo.com (E.E.A.)
2
Department of Mathematics, Faculty of Science, Mansoura University, Mansoura 35516, Egypt;
aylashin@mans.edu.eg
3
Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
4
Department of Mathematics and Computer Science, Faculty of Science, Port Said University,
Port Said 42521, Egypt
5
Department of Mathematics, Anand International College of Engineering, Jaipur 303012, India
6
International Center for Basic and Applied Sciences, Jaipur 302029, India
7
Department of Mathematics, Harish-Chandra Research Institute, Allahabad 211 019, India
8
Department of Mathematics, Netaji Subhas University of Technology, New Delhi 110078, India
* Correspondence: praveen.agarwal@anandice.ac.in or goyal.praveen2011@gmail.com
Abstract: In this paper, we intorduce a family of analytic functions in the open unit disk which is
bi-univalent. By the virtue of the Faber polynomial expansions, the estimation of n − th (n ≥ 3)
Taylor–Maclaurin coefficients | a
n
| is obtained. Furthermore, the bounds value of the first two
coefficients of such functions is established.
Keywords: faber polynomial; coefficient bounds; uniformly convex; uniformly starlike; univalent
functions; bi-univalent functions
1. Introduction
Faber polynomials, which were introduced by Faber in 1903 [1], play an important
role in the theory of functions of a complex variable and different areas of mathematics
and there is a rich literature [2–7] describing their properties and their applications. Given
a function h(z) of the form
h(z)= z + b
0
+ b
1
z
−1
+ b
2
z
−2
+ ...,
consider the expansion
ςh
′
(ζ )
h(ζ ) − w
=
∞
∑
n=0
Ψ
n
(w)ζ
−n
,
valid for all ζ in some neighborhood of ∞. The function Ψ
n
(w)= w
n
+
n
∑
k=1
a
nk
w
n−k
is a
polynomial of degree n, called the n-th Faber polynomial with respect to the function h(z).
In particular,
Ψ
0
(w)= 1, Ψ
1
(w)= w − b
0
,
Ψ
2
(w)= w
2
− 2b
0
w +(b
2
0
− 2b
1
),
Ψ
3
(w)= w
3
− 3b
0
w
2
+(3b
2
0
− 3b
1
)w +(b
3
0
+ 3b
1
b
0
− 3b
2
).
Let Ψ
n
(0)= F
n
(b
0
, b
1
, ... , b
n
), n ≥ 0, see ([8], p. 118). Let A denote the class of all
functions of the form:
f (z)= z +
∞
∑
n=2
a
n
z
n
, (1)
Symmetry 2021, 13, 302. https://doi.org/10.3390/sym13020302 https://www.mdpi.com/journal/symmetry