My Desk of Integrals has the final circumstance ##int frac dx x^2+a^2 ## for a 'normal' integral much too, not only the case the place ##a=one##. But I feel this being a Calculus homework difficulty it is anticipated with the OP to determine how to make it happen. Hints got https://gabletoppak.com/why-white-label-water-bottles-are-a-game-changer-for-your-brand/