Estimates on Initial Coefficient Bounds of Subclasses of Bi-Univalent Functions Defined by Generalized Differential Operator

In this present paper, we introduce two new subclasses HkΣ (α, δ, λ, μ, σ) and HkΣ (β, δ, λ, μ, σ) of normalized analytic bi-univalent functions defined in the open unit disk and associated with generalized differential operator. Further, we obtain bounds for the second and third Taylor- Maclaurin coefficients of the functions of these subclasses. Also, we obtain some consequences of results obtained.