What is the sum of the following series:
SUMMATION(n=1 to infiniti) -1/(n^2 + 9n + 20)
I tried using the forumula:
sum = a/(1-r)
But i cant get an exact value for r so i am not sure
For the sum, you can notice that each term is annulated by the one which follows, apart from the first term, -1/5.
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