lean_workbook_plus_19942

Proved

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

The question is to show that the equation has at least a root in $[0,2]$ and I exactly proved this.

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_19942 (f : ℝ → ℝ) (hf: f = fun (x:ℝ) => x^2 - 2) : ∃ x, x ∈ Set.Icc 0 2 ∧ f x = 0   :=  by sorry

Source