Lean-Workbook Plus 16723: Trigonometric inequality

Proved

WorkbookRestored.plus_16723

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

lean-workbookrestored-importssource-checked

If $0<k<\pi/2$ , then $1/\sin k>1$ .

Source: Lean-Workbook row lean_workbook_plus_16723 (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_16723 (k : ℝ) (h₁ : 0 < k) (h₂ : k < Real.pi / 2) : 1 / Real.sin k > 1   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, row lean_workbook_plus_16723; immutable original Prove2Me node d3f0c8a9-72c2-4ef0-8d64-7cd5be4903e9

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