My Desk of Integrals has the final case ##int frac dx x^2+a^2 ## as a 'regular' integral as well, not only the situation wherever ##a=one##. But I feel this getting a Calculus research difficulty it is expected of your OP to figure out how to get it done. Hints were https://gabletoppak.com/free-water-campaign-advertise-your-brand/