The greatest value that x^2 -yz, y^2 - xz, z^2 - xy can have
Source: IMO LongList 1970 - P36
May 21, 2011
inequalities proposedinequalities
Problem Statement
Let be non-negative real numbers satisfying
x^2 + y^2 + z^2 = 5 \text{ and } yz + zx + xy = 2.
Which values can the greatest of the numbers and have?