wavelengh equation needs to be double checked

[jiajiasun]

The equation for the wavelength of a plane wave in the frequency domain on this webpage (https://em.geosci.xyz/content/maxwell1_fundamentals/harmonic_planewaves_homogeneous/wavelength.html#harmonic-planewaves-homogeneous-wavelength-formula) does not seem right.

The wavelength is defined by 2X \pi/wavenumber, where wavenumber, in this case, would be either alpha or beta. Therefore, wavelength is 2X \pi/ \beta = 2 X pi X sqrt(2/(\omega \mu \sigma)).

It looks like a factor of 2Xpi is missing from the equation on the above webpage. Could anyone please double check?