# bugs – Wrong result with symbolic calculation in Mathematica

I am looking at the expansion of a time series
`Series (`$$left(sum_{s=1}^inftyfrac{r}{(1+k)^s}x^{s+1}right)^{-1}$$`{x, 0, 2}` and I get a result like

``````1 + (r x^2)/(1 + k) + SeriesData(x, 0, {}, 0, 3, 1)
``````

If I now simplify the above term first, I get $$frac{1}{1-frac{x^2 r}{1+k-x}}$$. Running the Series-command on the invers of this term, i.e., `Series(1-(x^2 r)/(1 + k - x)` gives me a different answer then the one above. This seems to be a bug or am I making a mistake here?