1+a^2 = ab+bc+ca + a^2=b(a+c)+a(a+c)=(a+c)(a+b)
1+b^2 = ab+bc+ca+b^2=ab+ac+bc+b^2=a(b+c)+b(b+c)=(a+b)(b+c)
1+c^2=ab+bc+ac+c^2=b(a+c)+c(a+c)=(a+c)(b+c)
inmultite ne dau:
(1+a^2)(1+b^2)(1+c^2)=(a+c)^2 x (a+b)^2 x (b+c)^2=[(a+c)(a+b)(b+c)]^2
deci sub radical avem un patrat deci radicalul este (a+c)(a+b)(b+c) care apartine lui Q
