theorem
  f1 is_continuous_in x0 & f1/.x0<>0 & f2 is_continuous_in x0 implies f2
  /f1 is_continuous_in x0
proof
  assume that
A1: f1 is_continuous_in x0 & f1/.x0<>0 and
A2: f2 is_continuous_in x0;
  f1^ is_continuous_in x0 by A1,Th36;
  then f2(#)(f1^) is_continuous_in x0 by A2,Th33;
  hence thesis by CFUNCT_1:39;
end;
