### Abstract

Let R denote the subclass of normalised analytic univalent functions f defined by f(z) = z + Σ_{n}
^{∞}=_{2}a _{n}z^{n} and satisfy Re{f′ (z)} > 0 where z ε D = { z : |z| < 1}. The object of the present paper is to introduce the functional |a_{2}a_{4} - a_{3}
^{2}|. For f ε R we give sharp upper bound for |a_{2}a_{4} - a _{3}
^{2}|.

Original language | English |
---|---|

Article number | 50 |

Pages (from-to) | 1-5 |

Number of pages | 5 |

Journal | Journal of Inequalities in Pure and Applied Mathematics |

Volume | 7 |

Issue number | 2 |

Publication status | Published - 2006 |

### Fingerprint

### Keywords

- Convex and starlike functions
- Fekete-Szegö functional
- Hankel determinant
- Positive real functions

### ASJC Scopus subject areas

- Mathematics(all)

### Cite this

*Journal of Inequalities in Pure and Applied Mathematics*,

*7*(2), 1-5. [50].

**Coefficient inequality for a function whose derivative has a positive real part.** / Janteng, Aini; Halim, Suzeini Abdul; Darus, Maslina.

Research output: Contribution to journal › Article

*Journal of Inequalities in Pure and Applied Mathematics*, vol. 7, no. 2, 50, pp. 1-5.

}

TY - JOUR

T1 - Coefficient inequality for a function whose derivative has a positive real part

AU - Janteng, Aini

AU - Halim, Suzeini Abdul

AU - Darus, Maslina

PY - 2006

Y1 - 2006

N2 - Let R denote the subclass of normalised analytic univalent functions f defined by f(z) = z + Σn ∞=2a nzn and satisfy Re{f′ (z)} > 0 where z ε D = { z : |z| < 1}. The object of the present paper is to introduce the functional |a2a4 - a3 2|. For f ε R we give sharp upper bound for |a2a4 - a 3 2|.

AB - Let R denote the subclass of normalised analytic univalent functions f defined by f(z) = z + Σn ∞=2a nzn and satisfy Re{f′ (z)} > 0 where z ε D = { z : |z| < 1}. The object of the present paper is to introduce the functional |a2a4 - a3 2|. For f ε R we give sharp upper bound for |a2a4 - a 3 2|.

KW - Convex and starlike functions

KW - Fekete-Szegö functional

KW - Hankel determinant

KW - Positive real functions

UR - http://www.scopus.com/inward/record.url?scp=33744723048&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33744723048&partnerID=8YFLogxK

M3 - Article

VL - 7

SP - 1

EP - 5

JO - Journal of Inequalities in Pure and Applied Mathematics

JF - Journal of Inequalities in Pure and Applied Mathematics

SN - 1443-5756

IS - 2

M1 - 50

ER -