a)
program tinhtong;
uses crt;
var n,i:integer;
A:real;
begin
clrscr;
write('Nhap n: '); readln(n);
A:=0;
for i:=1 to n do
A:=A+1/i;
write('A= ',A:2:2);
readln;
end.
b)
program tinhtong;
uses crt;
var n,i:integer;
A:real;
begin
clrscr;
write('Nhap n: '); readln(n);
A:=0;
for i:=1 to n do
A:=A+1/(i*(i+2));
write('A= ',A:2:2);
readln;
end.