My table of Integrals has the general situation ##int frac dx x^2+a^2 ## being a 'typical' integral much too, not just the situation where ##a=1##. But I think this getting a Calculus research difficulty it is anticipated with the OP to determine how to do it. Hints were given above. https://gabletoppak.com/aseptic-tetra-pak-vs-non-aseptic-gable-top-choosing-the-right-carton-for-your-needs/