My table of Integrals has the general situation ##int frac dx x^2+a^2 ## like a 'typical' integral much too, not just the case exactly where ##a=1##. But I think this getting a Calculus homework difficulty it is anticipated on the OP to determine how to get it done. Hints were https://gabletoppak.com/sustainability-in-action-gable-top-cartons-to-save-our-oceans/