为何
[xn]11−uG(x)=1n[wn−1]1(1−uw)2(wG−1(w))n[x^n]\dfrac{1}{1-uG(x)}=\dfrac 1n[w^{n-1}]\dfrac{1}{(1-uw)^2}\left(\dfrac{w}{G^{-1}(w)}\right)^n[xn]1−uG(x)1=n1[wn−1](1−uw)21(G−1(w)w)n
11−ux\dfrac{1}{1-ux}1−ux1 求导不应该是 u(1−ux)2\dfrac{u}{(1-ux)^2}(1−ux)2u 吗？
