Prove2Me

lean_workbook_plus_32385

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

Prove that sin⁡4(x)−cos⁡4(x)=−cos⁡(2x)\sin^4(x) - \cos^4(x) = -\cos(2x).

Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_32385 : ∀ x : ℝ, sin x ^ 4 - cos x ^ 4 = -cos (2 * x)   :=  by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook

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