埃特金不等距逐步插值。给定n个不等距节点的函数值及精度要求，使用埃特金逐步插值法计算指定插值点t处的函数近似值-Unequidistance interpolation with Aitken method. Using this method to get the near value of special point t ,and satify the functin values and presicion of n points.