lean_workbook_plus_17727

Open

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

Prove that $\sin 36^o = \cos 54^o$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_17727 : Real.sin (36 * π / 180) = Real.cos (54 * π / 180)   :=  by sorry

Source