My Desk of Integrals has the final scenario ##int frac dx x^two+a^2 ## as being a 'regular' integral as well, not just the situation wherever ##a=1##. But I think this being a Calculus homework trouble it is anticipated from the OP to figure out how to get it done. Hints https://gabletoppak.com/how-telanganas-amrabad-tiger-reserve-fights-back-against-its-biggest-threat-plastic/