State the necessary conditions for expanding the following function in ascending powers of 
, and find the first three terms of the expansion.
![\[\frac{2}{\left(1+x^{2}\right)\left(1-x\right)}\]](http://mathematics-dl.org/wp-content/ql-cache/quicklatex.com-ba6817ccb5dc6caaacb565ab413a6d85_l3.png "Rendered by QuickLaTeX.com")
Source: Porter, R.I. (1963). Further Elementary Analysis (2nd ed.). London: G. Bell & Sons. (Examples 16b, Question 9, p. 218)
