lean_workbook_plus_49730

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

$sin(x-y)sin(z-x)=\frac { 1 }{ 2 } [cos(2x-y-z)-cos(z-y)]$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_49730 (x y z : ℝ) : Real.sin (x - y) * Real.sin (z - x) = 1/2 * (Real.cos (2 * x - y - z) - Real.cos (z - y))   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook

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