reserve x,y,t for Real;

theorem Th10:
  x>=1 implies sqrt((x+1)/2)+sqrt((x-1)/2)>0
proof
  assume
A1: x>=1;
  then (x-1)/2>=0 by Th7;
  then
A2: sqrt((x-1)/2)>=0 by SQUARE_1:17,26;
  sqrt((x+1)/2)>=1 by A1,Th8;
  hence thesis by A2;
end;
