This is, perhaps, one of the most complicated computations done in this area using the Physics package. To the best of my knowledge never before performed on a computer algebra worksheet. It is exciting to present a computation like this one. At the end the corresponding worksheet is linked so that it can be downloaded and the sections be opened, the computation be reproduced. There is also a link to a pdf with everything open. Special thanks to Pascal Szriftgiser for bringing this problem. To reproduce the computations below, please update the Physics library with the one distributed from the Maplesoft R&D Physics webpage.
March 28 2019: updated taking advantage of new features of Maple 2019 and 2018.2.
Download HiddenSO4.pdf (all sections open)
Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft