Second Hankel Determinant for Certain Class of Functions Defined by Differential Operator

The objective of this paper is to obtain an upper bound of second Hankel determinant for a class of functions M_(α,β,λ,δ)^k (φ) defined in the open unit disc U by using the differential operator〖 D〗_(α,β,λ,δ)^k f(z). In addition, we give particular values to the parameters A,B and k to study special cases of the results of this article. The class M_(α,β,λ,δ)^k (φ) and the differential operator〖 D〗_(α,β,λ,δ)^k f(z).