MathDB
Romanian District Olympiad

Source: Grade XI

March 17, 2010
functionalgebra unsolvedalgebra

Problem Statement

Prove that any continuos function f:RR f: \mathbb{R}\rightarrow \mathbb{R} with f(x)\equal{}\left\{ \begin{aligned} a_1x\plus{}b_1\ ,\ \text{for } x\le 1 \\ a_2x\plus{}b_2\ ,\ \text{for } x>1 \end{aligned} \right. where a1,a2,b1,b2R a_1,a_2,b_1,b_2\in \mathbb{R}, can be written as: f(x)\equal{}m_1x\plus{}n_1\plus{}\epsilon|m_2x\plus{}n_2|\ ,\ \text{for } x\in \mathbb{R} where m1,m2,n1,n2R m_1,m_2,n_1,n_2\in \mathbb{R} and \epsilon\in \{\minus{}1,\plus{}1\}.