...oops... >It can be tricked: > >(%i17) max(acos(abs(x)+1), acos(abs(x) + 1) + 5); >(%o17) acos(abs(x)+1)+5 > >(The real domain of acos(abs(x) + 1) is empty.) Let's correct that: (%i17) max(acos(abs(x)+2), acos(abs(x) + 2) + 5); (%o17) acos(abs(x)+2)+5 (The real domain of acos(abs(x) + 2) is empty.) Barton