New subclass of analytic functions defined by subordination
نویسندگان
1 Department of Mathematics, Payame Noor University, Tehran, Iran
2 Department of Mathematics, Payame Noor University, Tehran, Iran
3 Department of Mathematics, Payame Noor University, Tehran, Iran
doi
10.22075/ijnaa.2018.13582.1706چکیده
By using the subordination relation $"\prec"$, we introduce an interesting subclass of analytic functions as follows:\begin{equation*}\mathcal{S}^*_{\alpha}:=\left\{f\in \mathcal{A}:\frac{zf'(z)}{f(z)}\prec \frac{1}{(1-z)^\alpha},\ \ |z|<1\right\},\end{equation*}where $0<\alpha\leq1$ and $\mathcal{A}$ denotes the class of analytic and normalized functions in the unit disk $|z|<1$. In the present paper, by the class $\mathcal{S}^*_{\alpha}$ and by the Nunokawa lemma we generalize a famous result connected to starlike functions of order $1/2$. Also, coefficients inequality and logarithmic coefficients inequality for functions of the class $\mathcal{S}^*_{\alpha}$ are obtained.