My Desk of Integrals has the overall situation ##int frac dx x^2+a^2 ## to be a 'conventional' integral much too, not simply the case in which ##a=1##. But I do think this staying a Calculus research difficulty it is expected of the OP to determine how to get it done. https://gabletoppak.com/how-white-label-water-bottles-can-skyrocket-your-business/