On Certain Subclasses of Univalent Functions and Radius Properties

نویسنده

  • M. OBRADOVIĆ
چکیده

Denote by A the class of all functions f , normalized by f(0) = f ′(0) − 1 = 0, that are analytic in the unit disk ∆ = {z ∈ C : |z| < 1}, and by S the subclass of univalent functions in ∆. Denote by S∗ the subclass consisting of functions f in S that are starlike (with respect to origin), i.e., tw ∈ f(∆) whenever t ∈ [0, 1] and w ∈ f(∆). Analytically, f ∈ S∗ if and only if Re (zf ′(z)/f(z)) > 0 in ∆. A function f ∈ A is said to belong to the class U if ∣∣∣∣f ′(z) ( z

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تاریخ انتشار 2009