High-frequency smoothing factor of weighted Jacobi
= High-frequency smoothing factor of weighted Jacobi
{title2=$\mu_\omega$}
For modes with $k/(n+1)\in[1/2,1]$ and large $n$, the worst attenuation factor is
$$
\mu_\omega=\max\{|1-\omega|,|1-2\omega|\}.
$$
It is minimized by $\omega=2/3$, for which $\mu_\omega=1/3$.