My Desk of Integrals has the overall situation ##int frac dx x^two+a^2 ## as a 'standard' integral also, not merely the situation in which ##a=1##. But I think this becoming a Calculus research trouble it is predicted on the OP to figure out how to do it. Hints got earlier https://gabletoppak.com/free-water-campaign-advertise-your-brand/