by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)
The following inequality is true: (a+1)21+(b+1)21+(c+1)21+8ab+bc+ca≥89.
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_14146 : ∀ a b c : ℝ, (1 / (a + 1) ^ 2 + 1 / (b + 1) ^ 2 + 1 / (c + 1) ^ 2 + (a * b + b * c + c * a) / 8) ≥ 9 / 8 := by sorry