lean_workbook_plus_36664

Proved

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

Let $a,b>0$ and $(1+a^2)(1+b^2)=4 .$ Prove that \n

a+b+ab\leq 3

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_36664 (a b : ℝ) (ha : 0 < a) (hb : 0 < b) (hab : (1 + a^2) * (1 + b^2) = 4) : a + b + a * b ≤ 3   :=  by sorry

Source