COEFFICIENT BOUNDS FOR CERTAIN CLASSES OF ANALYTIC FUNCTIONS

Abstract

Let  be the class of functions f(z)=z+∑_(n=2)^∞▒〖a_n z^n 〗 analytic in the unit disc E={z:|z|<1}. For starlike univalent function g(z)∈A, we denote by C and C^* the subclasses of functions f(z) in A satisfying Re{(〖zf〗^' (z))/(g(z))}>0 and Re{(f(z))/(g(z))}>0 respectively. We wish to obtain the sharp upper bounds for the functional |a_2 a_4-a_3^2 |.