English

Sufficient Conditions for Starlike Functions Associated with the Lemniscate of Bernoulli

Complex Variables 2013-03-04 v1

Abstract

Let -1\leq B<A\leq 1. Condition on \beta, is determined so that 1+\beta zp'(z)/p^k(z)\prec(1+Az)/(1+Bz)\;(-1<k\leq3) implies p(z)\prec \sqrt{1+z}. Similarly, condition on \beta is determined so that 1+\beta zp'(z)/p^n(z) or p(z)+\beta zp'(z)/p^n(z)\prec\sqrt{1+z}\;(n=0, 1, 2) implies p(z)\prec(1+Az)/(1+Bz) or \sqrt{1+z}. In addition to that condition on \beta is derived so that p(z)\prec(1+Az)/(1+Bz) when p(z)+\beta zp'(z)/p(z)\prec\sqrt{1+z}. Few more problems of the similar flavor are also considered.

Keywords

Cite

@article{arxiv.1303.0137,
  title  = {Sufficient Conditions for Starlike Functions Associated with the Lemniscate of Bernoulli},
  author = {S. Sivaprasad Kumar and Virendra Kumar and V. Ravichandran and Nak Eun Cho},
  journal= {arXiv preprint arXiv:1303.0137},
  year   = {2013}
}