My table of Integrals has the general situation ##int frac dx x^2+a^2 ## being a 'typical' integral too, not just the case exactly where ##a=1##. But I believe this getting a Calculus homework problem it is predicted with the OP to figure out how to do it. Hints got earlier https://gabletoppak.com/is-it-legal-to-sell-natural-mineral-water-in-gabletop-cartons-tetra-paks-and-aluminium-cans-in-india/