reserve n for Element of NAT,
  i for Integer,
  a, b, r for Real,
  x for Point of TOP-REAL n;

theorem Th14:
  for x being Point of TOP-REAL 2 st x is Point of Tunit_circle(2)
  & x`1 = 1 holds x`2 = 0
proof
  let x be Point of TOP-REAL 2 such that
A1: x is Point of Tunit_circle(2) and
A2: x`1 = 1;
  1^2 = |. x .|^2 by A1,Th12
    .= x`1^2+x`2^2 by JGRAPH_3:1;
  hence thesis by A2;
end;
