lean_workbook_plus_73111

Proved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

Let $a,b,c$ be positive reals such that $a(b+c)=bc.$ Then $\frac{a}{b+c} \leq \frac{1}{4}.$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_73111 (a b c : ℝ) (h1 : a > 0 ∧ b > 0 ∧ c > 0) (h2 : a * (b + c) = b * c) : a / (b + c) ≤ 1 / 4   :=  by sorry

Source