[Drozh]

т.е. 1 - 1 + 1/3 - 1/5 ....

Код:

var 
 n, i: integer;
 e,dr,sum: extended;

begin
e:=StrToFloat(Edit1.Text);
sum:=0;
dr:=1;
n:=-1;
i := 1

repeat
sum:=sum+dr;
inc(n,2);
i := -i
dr:=i/n;
until dr<e;

showmessage(FloatToStr(sum));
end;