function calc(x: integer; e: real): extended;
var k : integer;
    i: integer;
    x2: integer;
    n : cardinal;
    d : cardinal;
    v: real;
begin
    result := x;

    x2 := x*x;
    n := 1; d := 1; k := 1;
    i := 1;

    while (true) do begin
       inc(i, 2);
       n := n*x2;
       d := d*i*(i-1);
       v := n/d;
       if( v < e) break;
       k := -k;
       result := result + k*v;
    end;
end;