We consider an extremal
problem in geometry. Let λ be a real number and let A, B and C be arbitrary
points on the unit circle Γ. We give a full characterization of the extremal
behavior of the function f(M,λ) = MAλ+ MBλ+ MCλ, where M is a
point on the unit circle as well. We also investigate the extremal behavior
of ∑i=1nXPi, where the Pi, for i = 1,…,n, are the vertices of a regular
n-gon and X is a point on Γ, concentric to the circle circumscribed around
P1…Pn. We use elementary analytic and purely geometric methods in the
proof.