lean_workbook_plus_69691

Disproved

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

Using Cauchy-Schwarz we have : $9\left(a^{3} + 3b^{3} + 5c^{3}\right)\left(a + 3b + 5c\right)\ge9\left(a^{2} + 3b^{2} + 5c^{2}\right)^{2}\Leftrightarrow9\left(a^{3} + 3b^{3} + 5c^{2}\right)\ge\frac {9\left(a^{2} + 3b^{2} + 5c^{2}\right)^{2}}{a + 3b + 5c}$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_69691 : ∀ a b c : ℝ, 9 * (a ^ 3 + 3 * b ^ 3 + 5 * c ^ 3) * (a + 3 * b + 5 * c) ≥ 9 * (a ^ 2 + 3 * b ^ 2 + 5 * c ^ 2) ^ 2   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook

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