My desk of Integrals has the final scenario ##int frac dx x^two+a^2 ## as being a 'regular' integral too, not only the case where by ##a=1##. But I believe this being a Calculus homework issue it is expected with the OP to figure out how to do it. Hints got https://gabletoppak.com/sustainable-liquid-soap-packaging-why-gabletop-cartons-are-the-eco-friendly-choice/