lean_workbook_plus_74688

Disproved

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

Given $a+b+c=1$ , prove that $\frac{a}{(b+c)^2}+\frac{b}{(c+a)^2}+\frac{c}{(a+b)^2}\ge \frac{9}{4}.$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_74688 : ∀ a b c : ℝ, a + b + c = 1 → a / (b + c) ^ 2 + b / (c + a) ^ 2 + c / (a + b) ^ 2 >= 9 / 4   :=  by sorry

Source