Sharp Estimate of Fifth Coefficient for Ma Minda Starlike and Convex Functions

Abstract

\noindent In the present investigation, we find the sharp bound of fifth coefficient of analytic normalized function $f$ satisfying $z{f}^{\prime }(z)/f(z)\prec \phi (z)$ when coefficients of $\phi$ satisfy certain conditions. For an appropriate choice of $\phi$, the already known estimates for various other subclasses of starlike functions follow directly from the obtained result.

arXiv commentpaper revised and results improved