How Does WolframAlpha Calculate the Sum of (2n+1)/(n(n+1)(n+2))?

[antarctic]

can someone please explain how to get the result WolframAlpha gets at the following link:

http://www.wolframalpha.com/input/?i=sum+(2n+1)/(n+(n+1)+(n+2))

the sum is (2n+1)/(n (n+1) (n+2)) from n=1 to inf. and the result is 5/4 .

Thanks.

 

[mathman]

Did you try to get the derivation of the partial sum formula? Once you have that the final result is obvious.

 

[antarctic]

Thank you very much for the quick answer, but:

Did you try to get the derivation of the partial sum formula? Once you have that the final result is obvious.

how do you get the partial sum formula? I can't seem to get that