My Desk of Integrals has the final scenario ##int frac dx x^2+a^two ## being a 'common' integral way too, not only the case where ##a=one##. But I think this getting a Calculus homework issue it is predicted with the OP to determine how to do it. Hints were given above. https://gabletoppak.com/from-plastic-bottles-to-gabletop-cartons-a-step-toward-solving-the-plastic-pollution-crisis/