My desk of Integrals has the overall case ##int frac dx x^2+a^2 ## like a 'conventional' integral as well, not just the case where ##a=one##. But I think this getting a Calculus research issue it is expected with the OP to determine how to get it done. Hints got over. https://gabletoppak.com/glass-bottles-for-beer-soda-and-even-water-found-to-contain-toxic-levels-of-cancer-linked-microplastics-than-plastic-bottles-study-says/