My Table of Integrals has the final case ##int frac dx x^2+a^2 ## being a 'standard' integral as well, not just the situation the place ##a=1##. But I think this remaining a Calculus research difficulty it is expected of your OP to determine how to get it done. Hints were https://gabletoppak.com/beyond-beverages-gable-top-cartons-the-versatile-customized-packaging-solution/