My desk of Integrals has the general situation ##int frac dx x^two+a^2 ## for a 'common' integral much too, not just the situation where ##a=one##. But I believe this becoming a Calculus research problem it is expected with the OP to determine how to do it. Hints were given previously https://gabletoppak.com/beyond-beverages-gable-top-cartons-the-versatile-customized-packaging-solution/