can anyone help explain to me ?

I want to calculate the sum value of sn, with different manner, using matlab ,

its exact value is equal ,

the first way is:

the second way is :

if we talk about how the machine calculates, it is clear that we are not going to find the same result in relation to the exact value, but matlab gives me the same result, can anyone help me to find the error, this is my code matlab

%n=9,
%n=99,
n=999;
i=1:n;
format long
s1=1+sum(1./(i.^2+i));
s2=sum(1./(i.^2+i))+1;
s3=2+(1/(n+1));
s3 =

   2.001000000000000

s1 =

   1.498999999999999
   s2 =

   1.498999999999999

Answer 1

[Walter Roberson]

s2=sum(fliplr(1./(i.^2+i)))+1;