Prove2Me

Lean-Workbook Plus 49326: Trigonometric inequality

Proved
WorkbookRestored.plus_49326

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

lean-workbookrestored-importssource-checked

For 0<θ<π/20<\theta<\pi/2, tan⁡θ>0\tan\theta>0. This is the positivity component of the source statement.

Source: Lean-Workbook row lean_workbook_plus_49326 (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_49326 : ∀ θ : ℝ, θ ∈ Set.Ioo 0 (Real.pi / 2) → 0 < Real.tan θ   :=  by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, row lean_workbook_plus_49326; immutable original Prove2Me node 70a98598-3efe-4c9c-848b-f3e0d0d66483

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