4

Part of 2006 Greece Junior Math Olympiad

Problems(1)

Simple but rather nice !

Source: Greek olympiad , junior level - 2006, pr - 4

x , y

are real numbers such that

x^2 + xy + y^2 = 1

, find the least and the greatest value( minimum and maximum) of the expression

K = x^3y + xy^3

Babis Sorry !!! I forgot to write that these 4 problems( 4 topics) were JUNIOR LEVEL

algebrafunctiondomainquadraticsquadratic formula