My Table of Integrals has the final circumstance ##int frac dx x^two+a^two ## as being a 'regular' integral way too, not merely the case in which ##a=one##. But I think this staying a Calculus research problem it is expected on the OP to figure out how to do it. Hints https://gabletoppak.com/choosing-between-gable-top-packaging-and-plastic-bottles-for-your-beverage-business/