On a subfamily of starlike functions related to hyperbolic cosine function

Improved Window Based On Cosine Hyperbolic Function

A new simple form window with the application of FIR filter design based on the exponential function is proposed in this article. An improved window having a closed simple formula which is symmetric ameliorates ripple ratio in comparison with cosine hyperbolic window. The proposed window has been derived in the same way as Kaiser window, but its advantages have no power series expansion in its ...

Applications of subordination theory to starlike functions

Let $p$ be an analytic function defined on the open unit disc $mathbb{D}$ with $p(0)=1.$ The conditions on $alpha$ and $beta$ are derived for $p(z)$ to be subordinate to $1+4z/3+2z^{2}/3=:varphi_{C}(z)$ when $(1-alpha)p(z)+alpha p^{2}(z)+beta zp'(z)/p(z)$ is subordinate to $e^{z}$. Similar problems were investigated for $p(z)$ to lie in a region bounded by lemniscate of Bernoulli $|w^{2}-1|=1$ ...

On a class of starlike functions related to a shell-like curve connected with Fibonacci numbers

In this paper we investigate an interesting subclass SL of analytic univalent functions in the open unit disc on the complex plane. This class was introduced by Sokół [J. Sokół, On starlike functions connected with Fibonacci numbers, Folia Scient. Univ. Tech. Resoviensis 175 (1999) 111–116]. The class SL is strongly related to the class KSL considered earlier by the authors of the present work ...

On Uniformly Starlike Functions

These are normalized functions regular and univalent in E: IzI < 1, for which f( E) is starlike with respect to the origin. Let y be a circle contained in E and let [ be the center of y. The Pinchuk question is this: Iff(z) is in ST, is it true thatf(y) is a closed curve that is starlike with respect tof(i)? In Section 5 we will see that the answer is no. There seems to be no reason to demand t...

On Janowski Starlike Functions