With the aid of discrete Du's Transformation, we can solve the zero-state response of a discrete-time system usually described by a linear difference equation.

利用离散杜氏变换，给出线性离散系统零状态响应计算式，并可用以解线性差分方程；

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So, you remember from last time radial nodes are values of r at which the wave function and wave function squared are zero, so the difference is now we're just talking about the angular part of the wave function.

你们记得上次说径向节点在,波函数和波函数的平方,等于零的ｒ的处，现在的区别是我们讨论的是,角向波函数。

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