ChebyshevExpansion

代码说明：

  给定一个普通多项式p(x)，用列向量表示，阶次从高到低排列，此函数返回p(x)的切比雪夫多项式展开的系数，返回的的结果也是一个列向量，同样按切比雪夫多项式的阶次从高到低排列(Given a general polynomial p (x), with a column vector representation, the order highest to lowest, the function returns p (x) Chebyshev polynomial expansion coefficients of the returned result is a column vector, the same press cut the order highest to lowest Chebyshev polynomials)