lean_workbook_plus_38518

Proved

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

Let $f(x)$ and $g(x)$ be functions such that $f(x) = 4x + 3$ and $g(x) = \frac{x + 1}{4}$ . Evaluate $g(f(g(f(42))))$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_38518 (f g : ℝ → ℝ) (f_def : ∀ x, f x = 4 * x + 3) (g_def : ∀ x, g x = (x + 1) / 4) : g (f (g (f 42))) = 44   :=  by sorry

Source