用VB实现函数逼近的数值方法算法集。包括级数求和，切比雪夫逼近，积分和导数的切比雪夫逼近等五种函数逼近数值方法。-VB function approximation algorithm for the numerical method sets. Including the series, Chebyshev approximation, integral and derivative of Chebyshev approaching