It seems (to me) that Maxima is unable to perform the change of variable x*log(x)=u in the integral of (log(x)+1)*sqrt(1+(x*log(x))^2). Namely, (%i3) A : 'integrate((log(x)+1)*sqrt(1+(x*log(x))^2),x); (%i4) changevar(A,x*log(x)-u,u,x); returns the original integral. BTW, it can't find the antiderivative either. Milan --