Lean-Workbook Plus 14911: Trigonometric inequality

On $[0,\pi/2]$, sine is strictly increasing and cosine is strictly decreasing: if $x<y$ in this interval, then $\sin x<\sin y$ and $\cos y<\cos x$.

Source: Lean-Workbook row lean_workbook_plus_14911 (Apache-2.0). The unchanged proposition comes from the original record; its missing mathematical imports and namespaces are restored here.