lean_workbook_plus_9150

Disproved

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

Given $f(x) = (x+\sqrt{1+y^2})(y+\sqrt{1+x^2})$ , prove that if $f(x)=0$ , then $x=-y$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_9150 (x y : ℝ) (h₁ : (x + Real.sqrt (1 + y^2)) * (y + Real.sqrt (1 + x^2)) = 0) : x = -y   :=  by sorry

Source