EXTREMUM FOR A CLASS OF COEFFICIENT FUNCTIONALS

Ⅰ. INTRODUCTION Suppose f(z)=z+sum from n=2 to α_nz^n to be analytic in the unit disk |z|<1 and f(z)f’(z)≠0 (0<|z|<1), we say f(z) is a (α,β)-type spiral-like function. If there and α ∈ (-∞, +∞) such