We prove that erz is direction convexity preserving (DCP) for all 0

Let g be some set of non-constant analytic functions in the unit disk D, and for f e dg define The quantity where g u is the set of univalent functions in g, is called the John constant of g. We discuss where T k consists of the trinomials In particular, we find We also establish a conjecture of Rahman and Szynal for univalent trinomials in T k