MathDB
easy inequality (old problem)

Source: Netherlands 1994

June 28, 2009
inequalitiesalgebrapolynomialalgebra unsolved

Problem Statement

Three real numbers a,b,c a,b,c satisfy the inequality |ax^2\plus{}bx\plus{}c| \le 1 for all x \in [\minus{}1,1]. Prove that |cx^2\plus{}bx\plus{}a| \le 2 for all x \in [\minus{}1,1].