MathDB
Inequality in MVT?

Source: ISI Entrance UGB 2023/8

May 14, 2023
LMVTMVTcontinuitydifferentiabilityfunctioncalculus

Problem Statement

Let f ⁣:[0,1]Rf \colon [0,1] \to \mathbb{R} be a continuous function which is differentiable on (0,1)(0,1). Prove that either f(x)=ax+bf(x) = ax + b for all x[0,1]x \in [0,1] for some constants a,bRa,b \in \mathbb{R} or there exists t(0,1)t \in (0,1) such that f(1)f(0)<f(t)|f(1) - f(0)| < |f'(t)|.