A Class of Analytic Functions with Missing Coefficients

被引:8
|
作者
Yang, Ding-Gong [2 ]
Liu, Jin-Lin [1 ]
机构
[1] Yangzhou Univ, Dept Math, Yangzhou 225002, Jiangsu, Peoples R China
[2] Soochow Univ, Dept Math, Suzhou 215006, Jiangsu, Peoples R China
关键词
STARLIKE FUNCTIONS; DIFFERENTIAL-INEQUALITIES; CONVOLUTION PROPERTIES; SUBCLASSES;
D O I
10.1155/2011/456729
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Let T-n(A, B, gamma, alpha) (-1 <= B < 1, B < A, 0 < gamma <= 1 and alpha > 0) denote the class of functions of the form f(z) = z + Sigma(8)(k=n+1) a(k)z(k) (n is an element of N = {1, 2, 3, ... }), which are analytic in the open unit disk U and satisfy the following subordination condition f'(z) + alpha zf ''(z) < (1(Az)/(1 + Bz))(gamma), for (z is an element of U; A <= 1;0 < gamma < 1), (1 + Az)/(1 + Bz), for ( z is an element of U; gamma = 1). We obtain sharp bounds on Ref'(z), Ref(z)/z, vertical bar f(z)vertical bar, and coefficient estimates for functions f(z) belonging to the class T-n(A, B, gamma, alpha). Conditions for univalency and starlikeness, convolution properties, and the radius of convexity are also considered.
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页数:16
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