Hello, A few weeks ago I've had a question about integrals already - some stuff isn't solved yet, and apparently I can't convince Maple to help me. X:=sqrt(((z-1)^2+a^2)*((z+1)^2+a^2)); a^2/(-z^2+1+(((z-1)^2+a^2)*((z+1)^2+a^2))^(1/2)); int(%,z=0..infinity); How can these things be solved? Kind regards, Michael