lean_workbook_plus_1680
ProvedLet the series be . Prove that when .
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_1680 (a r : ℝ) (h : |r| < 1) : ∑' i : ℕ, a * r ^ i = a / (1 - r) := by sorry
Source
Let the series be . Prove that when .
import Mathlib.Analysis.Complex.Basic
theorem lean_workbook_plus_1680 (a r : ℝ) (h : |r| < 1) : ∑' i : ℕ, a * r ^ i = a / (1 - r) := by sorry