Estimation of the Second-Order Hankel Determinant of Logarithmic Coefficients for Two Subclasses of Starlike Functions

In our present study, two subclasses of starlike functions which are symmetric about the origin considered. These classes defined with use sigmoid function and trigonometric function, respectively. We estimate first four initial logarithmic coefficients, Zalcman functional, Fekete–Szegö bounds second-order Hankel determinants coefficients for class Sseg* improve obtained existing determinant second Ssin*. All that we obtain in this article proven to be sharp.