Bounds of Hankel Determinant for a Class of Univalent Functions

The authors study the coefficient condition for the class ℌ defined as the family of analytic functions ,(0)=0 and ′(0)=1, which satisfy ℜ[(1−)′()+(1+(′′())/(′()))]>,∈, where is a real number

Bounds for the Second Hankel Determinant of Certain Univalent Functions

The estimates for the second Hankel determinant a_2a_4-a_3^2 of analytic function f(z)=z+a_2 z^2+a_3 z^3+...b for which either zf'(z)/f(z) or 1+zf"(z)/f'(z) is subordinate to certain analytic function are investigated. The estimates for the Hankel determinant for two other classes are also obtained. In particular, the estimates for the Hankel determinant of strongly starlike, parabolic starlike, lemniscate starlike functions are obtained