My Desk of Integrals has the final situation ##int frac dx x^2+a^2 ## for a 'conventional' integral much too, not simply the situation wherever ##a=one##. But I think this becoming a Calculus homework difficulty it is expected of the OP to figure out how to get it done. Hints got https://gabletoppak.com/how-white-labeling-water-bottles-can-elevate-your-brand-identity/