MathDB
Inequality of function with integral and derivative

Source: VJIMC 2024, Category I, Problem 1

April 14, 2024
inequalitiesfunctioncalculusintegrationderivative

Problem Statement

Let f:RRf:\mathbb{R} \to \mathbb{R} be a continuously differentiable function. Prove that f(1)01f(x)dx12maxx[0,1]f(x).\left\vert f(1)-\int_0^1 f(x) dx\right\vert \le \frac{1}{2} \max_{x \in [0,1]} \vert f'(x)\vert.