# Thread: Find a sum using Method of Differences

1. ## Find a sum using Method of Differences

Hi, I need to find the summation of the series: (i+3)/[(i+1)(i+2)]*(1/2)^i from i=1 to ∞. I'm not sure how to find f(i). Any help would be appreciated. Thanks

3. ## Re: Find a sum using Method of Differences

I tried finding the partial fraction, and I tried separating the 2^i from the other term, but they didn't work. I have no idea how to work backwards for this question in order to get f(i).