lean_workbook_plus_48431

Proved

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

Prove that for a,b,c,d $\in$ R suh that a<b<c<d $(a+b+c+d)^2$ >=8(ac+bd)

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_48431 (a b c d : ℝ) (h1 : a < b ∧ b < c ∧ c < d) : (a + b + c + d) ^ 2 ≥ 8 * (a * c + b * d)   :=  by sorry

Source