[问答题]
1. By successive differentiation fir khc8x/p +vn0nd thed ..pjj s6nc,eqws4+r an1z7d first five non-zero terms in the Maclaurin series fjd dw.qn+ps,j1n674c.a e szror $f(x)=(2-2 x) \ln (1-x)+2 x $.
2. Deduce that, for $n \geq 2$ , the coefficient of $x^{n}$ in this series is $\frac{2}{n(n-1)}$ .
