My table of Integrals has the general case ##int frac dx x^2+a^2 ## to be a 'common' integral also, not merely the case where by ##a=one##. But I think this becoming a Calculus homework challenge it is expected of the OP to figure out how to do it. Hints were https://gabletoppak.com/why-paper-water-bottles-are-gaining-popularity-in-kerala/