“…where g is the extension of f −1 in U. Recently, several researchers such as (see [2,11,13,15,16,19]) obtained coefficients The main aim of the present investigation is to introduce and study two new subclasses of the function class Σ and find estimates on the initial coefficients |a 2 | and |a 3 | for functions in these new subclasses of the function class Σ using q-differential operator.…”