lean_workbook_plus_46244

Proved

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

Simplifying further, we get $1-\frac1n<c+d<1+\frac1n$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_46244 (n : ℕ) (hn : 1 < n) (c d : ℝ) (hcd : c + d = 1) :
  1 - 1 / n < c + d ∧ c + d < 1 + 1 / n   :=  by sorry

Source