1. The problem statement, all variables and given/known data Use differentiation to find a power series representation for f(x) = 1/ (1+x)^2 2. Relevant equations geometric series sum = 1/(1+x) 3. The attempt at a solution (1) I see that the function they gave is the derivative of 1/(1+x). (2) Therefore, (-1)*(d/dx)summation(x^n) = -1/(1+x)^2 (3) Differentiating the summation gives: (-1)*[summation (n)x^(n-1)] However, the book is telling me that for my second step (2) I should be getting d/dx [summation (-1)^n (x^n)]. Why is it becoming an alternating series here?