See Keong Lee

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The estimates for the second Hankel determinant a 2 a 4 – a 2 3 of the analytic function f (z) = z + a 2 z 2 + a 3 z 3 + · · · , for which either zf (z)/f (z) or 1 + zf (z)/f (z) is subordinate to a certain analytic function, are investigated. The estimates for the Hankel determinant for two other classes are also obtained. In particular, the estimates for(More)
Estimates on the initial coefficients are obtained for normalized analytic functions f in the open unit disk with f and its inverse g = f −1 satisfying the conditions that zf ′ (z)/f (z) and zg ′ (z)/g(z) are both subordinate to a starlike univalent function whose range is symmetric with respect to the real axis. Several related classes of functions are(More)
In this paper, some subclasses of meromorphic univalent functions in the unit disk ∆ are extended. Let U (p) denote the class of normalized univa-lent meromorphic functions f in ∆ with a simple pole at z = p > 0. Let φ be a function with positive real part on ∆ with φ(0) = 1, φ (0) > 0 which maps ∆ onto a region starlike with respect to 1 which is symmetric(More)
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