After obtaining the constants A and B It is comparatively easy to compute the integral ##int frac dx x^2 + 9 ## as it might now be prepared as two simpler integrals. I tried but I can't see how ##A,B## are constants? Out there in 3 regular dimensions of 300ml,500ml https://gabletoppak.com/choosing-between-gable-top-packaging-and-plastic-bottles-for-your-beverage-business/