
theorem Th05:
  for a,b,c being Complex st a <> 0 holds 2 * (a^2 * b) * c / a^2 = 2 * b * c
  proof
    let a,b,c be Complex;
    assume a <> 0;
    then (a^2 * b) * c / a^2 = b * c by Th04;
    hence thesis;
  end;
