lean_workbook_plus_44040

Proved

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

$\frac{x}{y}<\frac{x+z}{y+z}$ for $x,y,z\in\mathbb{R}^{+}$ and $x<y$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_44040 {x y z : ℝ} (hx : 0 < x) (hy : 0 < y) (hz : 0 < z) (hxy : x < y) : x / y < (x + z) / (y + z)   :=  by sorry

Source