Let R(beta, alpha) denote the class of functions of the form: f(z) = z + a(2)z(2) + a(3)z(3 +) ..., which are analytic in the open unit disk D = {z: vertical bar z vertical bar < 1} and satisfy the condition Re{f'(z) + az f'' (z)} > beta (a > 0; beta < 1; z epsilon D). We find extreme points of R (beta,a) and obtain some sharp bounds for certain linear problems. And we find number beta(a) (a >= 1) such that R(beta, a) is a subclass of S*, which denotes the class consisting of univalent starlike...
