My Desk of Integrals has the overall case ##int frac dx x^two+a^2 ## as a 'common' integral much too, not only the situation where by ##a=1##. But I feel this becoming a Calculus homework problem it is expected from the OP to determine how to get it done. Hints got https://gabletoppak.com/from-plastic-bottles-to-gabletop-cartons-a-step-toward-solving-the-plastic-pollution-crisis/