My desk of Integrals has the final case ##int frac dx x^two+a^two ## like a 'conventional' integral as well, not just the case wherever ##a=one##. But I believe this being a Calculus homework dilemma it is predicted from the OP to determine how to make it happen. Hints were given https://gabletoppak.com/sustainability-in-action-gable-top-cartons-to-save-our-oceans/