Now it is fun after 4 days of gnashing teeth. CRC integral tables clearly say, in 2 or 3 instances, how to solve the integral: ∫dx (a+x^2)^-2 . The solution looks like integration by parts but it is not. What’n’ell is it, it does work !!! I am glad to learn this, wouldn’t you know it, this is the form DKS energy integration reduces to.