by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)
In triangle ABC denote {α=ab+cβ=bc+aγ=ca+b . Prove that {α+β+γ+2=αβγ2(α+β+γ)≤αβ+βγ+γα
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_5727 (a b c α β γ : ℝ) (hx: a > 0 ∧ b > 0 ∧ c > 0) (hab : a + b > c) (hbc : b + c > a) (hca : a + c > b) (hα: α = (b + c) / a) (hβ: β = (c + a) / b) (hγ: γ = (a + b) / c) : (α + β + γ + 2 = α * β * γ ∧ 2 * (α + β + γ) ≤ α * β + β * γ + γ * α) := by sorry