My desk of Integrals has the final case ##int frac dx x^2+a^2 ## being a 'standard' integral far too, not just the case in which ##a=one##. But I do think this currently being a Calculus homework issue it is anticipated with the OP to determine how to do it. Hints https://gabletoppak.com/water-in-a-sustainable-box-the-future-of-eco-friendly-hydration/