How to find the indefinite integral of the product of X and TaNx

How to find the indefinite integral of the product of X and TaNx

The product of this problem is not an elementary function (elementary function: function expressed by finite terms), but a non elementary function expressed by infinite terms
On calculus: so far, differential can be calculated, but integral may not be able to be integrated. Generally speaking, there are direct method, substitution method and division method for integral. Maybe there will be a big breakthrough in mathematical field in the future. It's not surprising to find a better integral method to integrate all functions, but at least not now, So there are many seemingly simple functions, such as ∫ SiNx
/It's a pity that X and DX can't be integrated by the existing methods
So you don't have to study the integral of this type of non elementary function too much. If you are interested, you can study the higher function at a deeper level!