My desk of Integrals has the general situation ##int frac dx x^two+a^2 ## being a 'normal' integral too, not simply the case wherever ##a=one##. But I believe this currently being a Calculus homework trouble it is expected of the OP to figure out how to get it done. Hints were https://gabletoppak.com/gabletop-pak-leading-the-way-as-milk-carton-manufacturers-in-india/