My table of Integrals has the general situation ##int frac dx x^two+a^two ## for a 'common' integral way too, not just the case where by ##a=one##. But I think this remaining a Calculus research trouble it is predicted from the OP to determine how to make it happen. Hints got https://gabletoppak.com/aseptic-tetra-pak-vs-non-aseptic-gable-top-choosing-the-right-carton-for-your-needs/