My desk of Integrals has the final case ##int frac dx x^2+a^two ## as being a 'standard' integral also, not simply the case where by ##a=1##. But I do think this becoming a Calculus research issue it is anticipated in the OP to figure out how to do it. Hints https://gabletoppak.com/what-makes-gabletop-pak-cartons-a-better-choice-than-plastic-bottles/