lean_workbook_plus_4358

Proved

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

Let $a,b\in [1,2]$ . Prove that \n

\frac{a+1}{b+2}+\frac{b+1}{a+2} \leq \frac{3}{2}

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_4358 (a b : ℝ) (ha : 1 ≤ a ∧ a ≤ 2) (hb : 1 ≤ b ∧ b ≤ 2) : (a + 1) / (b + 2) + (b + 1) / (a + 2) ≤ 3 / 2   :=  by sorry

Source