My table of Integrals has the general situation ##int frac dx x^2+a^2 ## like a 'typical' integral much too, not just the situation where ##a=one##. But I do think this being a Calculus homework issue it is expected from the OP to figure out how to do it. Hints were https://gabletoppak.com/is-it-legal-to-sell-natural-mineral-water-in-gabletop-cartons-tetra-paks-and-aluminium-cans-in-india/