My Desk of Integrals has the overall situation ##int frac dx x^two+a^2 ## for a 'conventional' integral too, not only the case where ##a=one##. But I think this currently being a Calculus homework trouble it is expected with the OP to determine how to do it. Hints were given above. https://gabletoppak.com/single-use-plastic-water-bottles-will-not-be-available-in-himachal-from-june-1-use-glass-bottles-and-dispensers-instead/