a) Express the function g(x)=\frac{3 x^{2}-x+2}{(1-x)\left(1+x^{2}\right)} as the sum of real partial fractions. \text { b) Hence calculate the power series } \sum u_{n} x^{n} \text { of } g(x) \text { and determine its radius of } convergence. You must give the terms up to degree five, at least.