Establish the existence of two irrational numbers A and B, such
that the number AB is rational, or prove that such numbers do not exist.
Answer:
Let X = sqr(2)sqr(2), and B = sqr(2).
Either X is irrational; then, A = X, and AB = [ sqr(2)sqr(2) ] sqr(2)
= 2 is rational.
Or X is rational; then A = B, and AB = X.