The denominator of f ( x ) {\displaystyle f(x)} factors as ( 2 + x ) ( 1 − x ) {\displaystyle (2+x)(1-x)} . Can you write f ( x ) {\displaystyle f(x)} as a sum A 2 + x + B 1 − x {\displaystyle {\frac {A}{2+x}}+{\frac {B}{1-x}}} , for some choices of A , B {\displaystyle A,B} ? Do these summands look familiar?
