Hello, I am trying to compute an integral, int(1/3*(-6*u2^2+u2*(3*z+9*u3)+z^2-5*z*u3-2*u3^2)*(z-u3)*(z-u2)/(u2-u3)^4, u3 = z .. 1); Warning, unable to determine if u2 is between z and 1; try to use assumptions or set _EnvAllSolutions to true O.K., I try with assumptions: int(1/3*(-6*u2^2+u2*(3*z+9*u3)+z^2-5*z*u3-2*u3^2)*(z-u3)*(z-u2)/(u2-u3)^4, u3 = z .. 1) assuming u2