scholarly journals Starlikness Associated with Cosine Hyperbolic Function

Mathematics ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 1118 ◽  
Author(s):  
Abdullah Alotaibi ◽  
Muhammad Arif ◽  
Mohammed A. Alghamdi ◽  
Shehzad Hussain

The main contribution of this article is to define a family of starlike functions associated with a cosine hyperbolic function. We investigate convolution conditions, integral preserving properties, and coefficient sufficiency criteria for this family. We also study the differential subordinations problems which relate the Janowski and cosine hyperbolic functions. Furthermore, we use these results to obtain sufficient conditions for starlike functions connected with cosine hyperbolic function.

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Saira Zainab ◽  
Ayesha Shakeel ◽  
Muhammad Imran ◽  
Nazeer Muhammad ◽  
Hira Naz ◽  
...  

This article deals with the q -differential subordinations for starlike functions associated with the lemniscate of Bernoulli and cardioid domain. The primary goal of this work is to find the conditions on γ for 1 + γ z ∂ q   h z / h n   z   ≺ 1 + z , where h z is analytic function and is subordinated by the function which is producing cardioid domain as its image domain while mapping the open unit disk. Along with this, certain sufficient conditions for q -starlikeness of analytic functions are determined.


2021 ◽  
Vol 66 (3) ◽  
pp. 457-470
Author(s):  
Swati Anand ◽  
V. Ravichandran ◽  
Sushil Kumar

"Theory of differential subordination provides techniques to reduce differential subordination problems into verifying some simple algebraic condition called admissibility condition.We exploit the first order differential subordination theory to get several sufficient conditions for function satisfying several differential subordinations to be a Janowski function with positive real part. As applications, we obtain suffcient conditions for normalized analytic functions to be Janowski starlike functions."


2014 ◽  
Vol 32 (2) ◽  
pp. 229
Author(s):  
Ali Muhammad

In this paper, we investigate interesting properties and sufficient conditions for meromorphic starlike functions in the punctured unit disc.


Author(s):  
Herb Silverman

We investigate an expression involving the quotient of the analytic representations of convex and starlike functions. Sufficient conditions are found for functions to be starlike of a positive order and convex.


ISRN Geometry ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
Neng Xu

Let f(z) be analytic in the unit disk U={z:|z|<1} with f(0)=f'(0)-1=0 and (f(z)/z)f'(z)≠0. By using the method of differential subordinations, we determine the largest number α(β,λ,μ,m) such that, for some β,λ,μ, and m, the differential subordination λzf'(z)/f(z)1-μ1+(zf''(z)/f'(z))-zf'(z)/f(z)+zf'(z)/f(z)m≺1+z/1-zα(β,λ,μ,m)(z∈U) implies zf'(z)/f(z)≺1+z/1-zβ. Some useful consequences of this result are also given.


Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 629 ◽  
Author(s):  
Muhammad Arif ◽  
Omar Barkub ◽  
Hari Srivastava ◽  
Saleem Abdullah ◽  
Sher Khan

The motive behind this article is to apply the notions of q-derivative by introducing some new families of harmonic functions associated with the symmetric circular region. We develop a new criterion for sense preserving and hence the univalency in terms of q-differential operator. The necessary and sufficient conditions are established for univalency for this newly defined class. We also discuss some other interesting properties such as distortion limits, convolution preserving, and convexity conditions. Further, by using sufficient inequality, we establish sharp bounds of the real parts of the ratios of harmonic functions to its sequences of partial sums. Some known consequences of the main results are also obtained by varying the parameters.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yusuf Pandir ◽  
Halime Ulusoy

We firstly give some new functions called generalized hyperbolic functions. By the using of the generalized hyperbolic functions, new kinds of transformations are defined to discover the exact approximate solutions of nonlinear partial differential equations. Based on the generalized hyperbolic function transformation of the generalized KdV equation and the coupled equal width wave equations (CEWE), we find new exact solutions of two equations and analyze the properties of them by taking different parameter values of the generalized hyperbolic functions. We think that these solutions are very important to explain some physical phenomena.


2017 ◽  
Vol 67 (4) ◽  
Author(s):  
Mamoru Nunokawa ◽  
Janusz Sokół

AbstractIn this work we present a new geometric approach to some problems in differential subordination theory. In the paper some sufficient conditions for function to be starlike or univalent or to be in the class of Carathéodory functions are obtained. We also discuss the new results closely related to the generalized Briot-Bouquet differential subordination.


1974 ◽  
Vol 18 (5) ◽  
pp. 526-532
Author(s):  
Stanley Lippert

A review of some studies of skill acquisition indicates that a simple hyperbolic function fits data on individual performance well. The function yields an explicit value of prior experience related to the task. The particular function for an individual can be adjusted to a “hypothetical first” trial which is common to other members of the sample population. The individual constants in the adjusted functions may then be averaged arithmetically to give a mean function, which is also an hyperbola. Standard deviations of the values of the constants may also be computed. These too will be hyperbolic functions.


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