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American International Journal of Research in Science, Technology, Engineering & Mathematics

Available online at http://www.iasir.net

ISSN (Print): 2328-3491, ISSN (Online): 2328-3580, ISSN (CD-ROM): 2328-3629 AIJRSTEM is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research)

Some Properties of a Subclass of Univalent Functions Related to Hypergeometric Function and its Integral V. A. Chougule1 and U. H. Naik 2 Department of Mathematics, College of Engineering, Malegaon Bk, Baramati, Pune, Maharashtra, INDIA 2 Department of Mathematics, Willingdon College, Sangli, Maharashtra, INDIA

1

Abstract: In this paper we defined class S(Îą, β, Îť) by using the class S(Îť, Îą) (see[1]) and obtained condition for hypergeometric function F(a,b;c;z)and its integral to be in this class. Keywords: univalent functions, starlike functions, convex functions, differential operator, hypergeometric function. I. Introduction Let A denotes the class of functions of the form, ∞

đ?‘“(đ?‘§) = đ?‘§ + ∑ đ?‘Žđ?‘› đ?‘§ đ?‘›

(1.1)

đ?‘›=2

which are analytic and univalent in the unit disk U = {z : |z| < 1}. Let S be subclass of A, of functions univalent in U and T be subclass of S, consisting of functions of the form, ∞

đ?‘”(đ?‘§) = đ?‘§ − ∑ đ?‘?đ?‘› đ?‘§ đ?‘› (đ?‘?đ?‘› ≼ 0 )

(1.2)

đ?‘›=2

Goodman [2] introduced classes UCV and UST of uniformly convex and uniformly starlike functions. Further Ronning studied classes UCV and UST (for more details see [3]). Among several interesting definitions given in literature (See, [4], [5], [6], [7] and many others) we recall the following, Definition 1.1 The function f(z) defined by Equation (1.1), which satisfies the condition, đ?‘§đ?‘“ ′ (đ?‘§) đ?‘§đ?‘“ ′ (đ?‘§) đ?‘…đ?‘’ { − đ?›ź} ≼ đ?›˝ | − 1| đ?‘“(đ?‘§) đ?‘“(đ?‘§) where, 0 ≤ đ?›ź < 1, đ?›˝ ≼ 0 is called as β - Uniformly starlike function of order Îą. The class of β – Uniformly starlike function of order Îą is denoted by β −S(Îą). 

�� ′ (�)

When β = 0, i.e. if đ?‘…đ?‘’ {

} ≼ �, the function f(z) is called starlike of order ι.

�(�)

 When β = 1, the function f(z) ∈ UST  The function f(z) is called starlike, if both Îą and β are zero. Definition 1.2 The function f(z) defined by Equation (1.1), which satisfies the condition, đ?‘§đ?‘“ " (đ?‘§) đ?‘§đ?‘“ " (đ?‘§) đ?‘…đ?‘’ {1 + ′ − đ?›ź} ≼ đ?›˝ | ′ | đ?‘“ (đ?‘§) đ?‘“ (đ?‘§) where, −1 ≤ Îą < 1, β ≼ 0 is called β - Uniformly Convex function of order Îą. The class of β - Uniformly convex function of order Îą is denoted by β −K(Îą). 

When β = 0, i.e. {1 +

�� " (�) � ′ (�)

} ≼ � , if the function f(z) is called convex of order ι .

 When β = 1, the function f(z) ∈ UCV  The function f(z) is called convex, if both Îą and β are zero. The classes β −S(Îą) and β −K(Îą) were studied by Goodman, Ronning and Minda and Ma. (see [8], [2], [3], [4]). Definition 1.3 The (Gaussian) hypergeometric function F(a,b;c;z) is defined as,

AIJRSTEM 15-726; Š 2015, AIJRSTEM All Rights Reserved

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