An upper bound to the nonlinear functional for certain subclasses of analytic functions associated with Hankel determinant
Abstract
The objective of this paper is to obtain an upper bound to the second Hankel determinant for the functions belonging to strongly starlike and convex functions of order α(0 < α ≤ 1). Further, we introduce a subclass of analytic functions and obtain the same coefficient inequality for the functions in this class, using Toeplitz determinants.