lean_workbook_plus_73087

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

with equality iff $\sin A \cos B = \sin B \cos A \Longrightarrow \sin (A-B) = 0$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_73087 :
  ∀ A B : ℝ, (sin A * cos B = sin B * cos A) ↔ sin (A - B) = 0   :=  by sorry

Source