  The present paper is an evolution of the Mengoli's series to the set of
rational numbers, which eventually will allow developing the summation, by
limits, obtaining the value of zeta(2); problem which Mengoli himself was the
first to postulate. More specifically in this paper is postulated and
demonstrated the function which resolves every summation since n=1 to infinite
of the type 1/((n+a/w)(n+b/w)...(n+z/w)) for all a,b,...,z,w belonging to the
set of integers, where a>b>...>z are different; a/w,b/w,...,z/w not equal to
-1,-2,-3,... Finally limits to the past summation is applied to demonstrate
zeta(2).
