lean_workbook_plus_57900

Proved

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

Find the value of the infinite geometric progression with first term 1 and common ratio $\frac{1}{2}$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_57900 (a : ℝ) (h : a = 1 / 2) : ∑' i : ℕ, a ^ i = 2   :=  by sorry

Source