My desk of Integrals has the final scenario ##int frac dx x^2+a^2 ## like a 'standard' integral too, not just the situation where by ##a=1##. But I feel this remaining a Calculus research difficulty it is anticipated of the OP to determine how to do it. Hints got earlier mentioned. https://gabletoppak.com/chikkamagaluru-dc-to-declare-mullayyanagiri-hill-station-plastic-free-zone-on-world-earth-day/