AXIOMS, cilt.11, sa.10, 2022 (SCI-Expanded)
In our present investigation, we introduce and study some new subclasses of analytic functions associated with Ruscheweyh differential operator D-r. We obtain a Fekete-Szego inequality for certain normalized analytic function defined on the open unit disk for which [(D(r)l)'(z)](theta) (z(D(r)l)'(z)/(D(r)l)(z))(1-theta) (sic) e(z) (0 <= theta <= 1) lies in a starlike region with respect to 1 and symmetric with respect to the real axis. As a special case of this result, the Fekete-Szego inequality for a class of functions defined through Poisson distribution series is obtained.