MathDB
$g(x)=C\cdot10^{-|x-d|}$

Source: Moldova TST 1993

August 8, 2023
functionparameterization

Problem Statement

Let f:RRf:\mathbb{R}\rightarrow\mathbb{R} be a function defined as the maximum of a finite number of functions g:RRg:\mathbb{R}\rightarrow\mathbb{R} of the form g(x)=C10xdg(x)=C\cdot10^{-|x-d|} (with different values of parameters dd{} and C>0C>0). For real numbers a<ba<b we have f(a)=f(b)f(a)=f(b). Prove that on the segment [a;b][a;b] the sum of legnths of segments on which ff is increasing is equal to the sum of legnths of segments on which ff is decreasing.