中文说明：运用matlab求解x（n）=a 的n 次幂，其中a为实数，当a的绝对值小于1的时候，序列是收敛的，而当a的绝对值大于1的时候，序列是发散的，实指数信号的matlab实现为：n=n1：dt：n2；x=a.^n.比较不同的是指数信号。
English Description：
Matlab is used to solve the nth power of X (n) = a, where a is a real number. When the absolute value of a is less than 1, the sequence is convergent. When the absolute value of a is greater than 1, the sequence is divergent. The matlab implementation of real exponential signal is: n = N1: DT: N2; X = A. ^ n.