IMO Shortlist 1989 problem 24
Dodao/la: arhiva2. travnja 2012.
on the sphere of radius 1, what is the maximum value that
can take? Determine all configurations for which this maximum is attained. (Or: determine the diameter of any set
for which this maximum is attained.)
Izvor: Međunarodna matematička olimpijada, shortlist 1989