My table of Integrals has the general case ##int frac dx x^2+a^2 ## as being a 'conventional' integral way too, not just the case in which ##a=1##. But I think this currently being a Calculus research dilemma it is expected in the OP to determine how to do it. Hints https://gabletoppak.com/from-plastic-bottles-to-gabletop-cartons-a-step-toward-solving-the-plastic-pollution-crisis/