theorem Th9:
  seq1 is divergent_to+infty & seq2 is bounded_below implies seq1+
  seq2 is divergent_to+infty
proof
  assume that
A1: seq1 is divergent_to+infty and
A2: seq2 is bounded_below;
  let r;
  consider M be Real such that
A3: for n holds M<seq2.n by A2;
  consider n such that
A4: for m st n<=m holds r-M<seq1.m by A1;
  take n;
  let m;
  assume n<=m;
  then r-M<seq1.m by A4;
  then r-M+M<seq1.m+seq2.m by A3,XREAL_1:8;
  hence thesis by SEQ_1:7;
end;
