Prove2Me

lean_workbook_plus_47859

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

Prove that 2>tan⁡θ(1−sin⁡θ)2 > \tan\theta(1-\sin\theta) for 0<θ<π20 < \theta < \frac{\pi}{2}.

Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_47859 (θ : ℝ) (h1 : 0 < θ) (h2 : θ < Real.pi / 2) : 2 > Real.tan θ * (1 - Real.sin θ)   :=  by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook

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