My table of Integrals has the overall case ##int frac dx x^2+a^2 ## for a 'common' integral way too, not just the situation the place ##a=1##. But I think this currently being a Calculus homework issue it is anticipated on the OP to figure out how to do it. Hints https://gabletoppak.com/reducing-microplastics-why-gable-top-cartons-are-better-than-plastic-water-bottles/