Lean-Workbook Plus 8749: Trigonometric inequality

Proved

WorkbookRestored.plus_8749

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

lean-workbookrestored-importssource-checked

If $0<x\le\pi/2$ , then $0<\sin x\le1$ .

Source: Lean-Workbook row lean_workbook_plus_8749 (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_8749 : ∀ x : ℝ, 0 < x ∧ x ≤ π / 2 → 0 < sin x ∧ sin x ≤ 1   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, row lean_workbook_plus_8749; immutable original Prove2Me node e83167e5-49b8-4166-b10a-16fae07390d6

View graph