Delphi - Lab8.4

Program lab8_4;
Uses Math;
var
  n, k: integer;
  sum: real;

function xi(i: integer) : float;
begin
  if i = 1 then
     xi := 1
  else
     xi := 0.3*xi(i-1);
end;

function yi(i: integer) : float;
begin
  if i = 1 then
     yi := 1
  else
     yi := yi(i-1) + power(xi(i-1), 2);
end;

begin

writeln('input n: ');
readln(n);
sum := 0;
for k := 1 to n do
    sum := sum + xi(k)/(1+abs(yi(k) - xi(k)));

writeln('sum = ', sum);
readln;
end.