$s=2\pi n_{1}-x+\pi -\arccos(\frac{2}{3})\text{, }n_{1}\in \mathrm{Z}$
$s=2\pi n_{2}-x+\pi +\arccos(\frac{2}{3})\text{, }n_{2}\in \mathrm{Z}$

$x=2\pi n_{1}-s+\pi -\arccos(\frac{2}{3})\text{, }n_{1}\in \mathrm{Z}$
$x=2\pi n_{2}-s+\pi +\arccos(\frac{2}{3})\text{, }n_{2}\in \mathrm{Z}$