1. The problem statement, all variables and given/known data integrate arctan(1/x) 2. Relevant equations 3. The attempt at a solution z=arctan(1/x) dx=-dz(x^2-1) now its the integral of z(x^2-1)dz let u =X^2-1 du=2x dv=-udu v=-u^2/2 integral=(x^2-1)(-u^2/2) - int (-u^2)(2x) this is where i got stuck but i think im doing the z substitution incorrectly. is it even necessary to sub z? Thanks!