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Lean-Workbook Plus 6740: Trigonometric identity

Proved
WorkbookRestored.plus_6740

by wamlart · Sep 12, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

lean-workbookrestored-importssource-checked

Show that sin⁡(x+2π)=sin⁡x\sin (x+2\pi) = \sin x .

Source: Lean-Workbook row lean_workbook_plus_6740 (Apache-2.0). The unchanged proposition comes from the original record; its missing mathematical imports and namespaces are restored here.

Preamble
import Mathlib.Analysis.SpecialFunctions.Trigonometric.Basic
open Real
Formal statement
theorem WorkbookRestored.plus_6740 (x : ℝ) : sin (x + 2 * π) = sin x   :=  by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, row lean_workbook_plus_6740; immutable original Prove2Me node 76e058cd-95a1-4a77-a9c7-6780586f2141

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