Abstract
In this paper, we study the class đcos of normalized analytic functions f satisfying 1 + z f''(z) / f'(z) âș cos(z). We obtain the sharp coefficient bounds and Hankel determinants of second and third order for functions for đcos. We also present the similar results for inverse and logarithm coefficients. These results improve the results recently obtained in [Marimuthu et al.: Coefficient estimates for starlike and convex functions associated with cosine function, Hacet. J. Math. Stat. 52 (2023), 596â618. Furthermore, our results provide examples of invariance of the coefficient bounds among the subclass of convex functions.
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(Communicated by StanisĆawa Kanas)
References
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Artikel in diesem Heft
- Joins of normal matrices, their spectrum, and applications
- On isbellâs density theorem for bitopological pointfree spaces II
- Every positive integer is a sum of at most n + 2 centered n-gonal numbers
- A generalisation of q-additive functions
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- On solutions to q-difference equations for q-appell functions in the spirit of Olsson and Exton
- Numerical implementation of solving a boundary value problem including both delay and parameter
- Solutions of second order iterative boundary value problems with nonhomogeneous boundary conditions
- Global attractivity of nonlinear delay dynamic equations on time scales via Lyapunov functional method
- On pseudo almost periodic solutions of the parabolic-elliptic Keller-Segel systems
- A note on derivations into annihilators of the ideals of banach algebras
- Characterization of nonlinear mixed skew lie and jordan n-Type derivation on â-Algebras
- Linear and uniformly continuous surjections between Cp-spaces over metrizable spaces
- A goodness-of-fit test for testing exponentiality based on normalized dynamic survival extropy
- Monotonicity results of ratio between two normalized remainders of Maclaurin series expansion for square of tangent function