题目

4.[单选题]函数f(z)=(1)/(z(z-1))在圆环1A. (1)/(z)sum_(n=0)^inftyz^nB. -(1)/(z)sum_(0=n)^inftyz^nC. (1)/(z^2)sum_(n=0)^infty((1)/(z))^nD. -(1)/(z^2)sum_(0=n)^infty((1)/(z))^n

4.[单选题]函数$f(z)=\frac{1}{z(z-1)}$在圆环1<|z|<∞内展开成洛朗级数( )

A. $\frac{1}{z}\sum_{n=0}^{\infty}z^{n}$

B. $-\frac{1}{z}\sum_{0=n}^{\infty}z^{n}$

C. $\frac{1}{z^{2}}\sum_{n=0}^{\infty}(\frac{1}{z})^{n}$

D. $-\frac{1}{z^{2}}\sum_{0=n}^{\infty}(\frac{1}{z})^{n}$

题目解答

C. $\frac{1}{z^{2}}\sum_{n=0}^{\infty}(\frac{1}{z})^{n}$