Let $\mathcal{ S}_u^*$ denote the class of all analytic functions $f$ in the unit disk $\mathbb{ D}:=\{ z\in\mathbb{ C}:|z|<1\}$, normalized by $f(0)=f'(0)-1=0$ that satisfies the inequality $\left|zf'(z)/f(z)-1\right|<1$ in $\mathbb{ D}$. In the present article, we obtain the sharp estimate of Hankel determinants whose entries are coefficients of $f\in\mathcal{ S}_u^*$, logarithmic coefficients of $f\in\mathcal{ S}_u^*$ and coefficients of inverse of $f\in\mathcal{ S}_u^*$, respectively. We also obtain, the sharp estimate of the successive coefficients for functions in the class $\mathcal{ S}_u^*$.
Categories: math.CV