I would like to thank you both, Bianca and Gianluca, for helping me. About Bianca's idea, I also was not able to improve the result by using Assumptions. About Gianluca's, his suggestion is interesting, but it depends on the previous knowledge about the ArcTan
function in the solution.
The ideal way of solving that integral, which I was expecting to find, was to use the functions and options already provided by Mathematica, such as FullSimplify
, Expand
, Factor
, PowerExpand
, ExpToTrig
, Assumptions
, and many others.