I know this is not a school forum... But I think this problem has been solved multiple times all over the internett, but now I am unable to find a complete soultion for this problem. 1/(x^4+1) I think it also have been solved multiple times on this site. Could anyone help me find a complete solution? (Link to thread here) The basic outline I remember from reading about it before is 1. Rationalize the denominator 2. Split the integral into two mean integrals 3. Divide top and bottom by x^2 4. Factor 5. Substitution But as I said, I am unable to find it now.