On certain properties of some subclasses of univalent functions

Abstract

In this paper we determine the disks $|z|<r\le 1$ where for different classes of univalent functions, we have the property $$\mathrm{Re}\left\{2\frac{z{f}^{\prime }(z)}{f(z)}-\frac{z{f}^{\prime \prime }(z)}{f^{\prime }(z)}\right\}>0(|z|<r).$$