My Desk of Integrals has the final case ##int frac dx x^two+a^two ## like a 'normal' integral much too, not just the case where ##a=1##. But I feel this staying a Calculus research challenge it is anticipated in the OP to determine how to get it done. Hints got over. https://gabletoppak.com/choosing-between-gable-top-packaging-and-plastic-bottles-for-your-beverage-business/