考虑在一个固定区间上用插值逼近一个函数。显然，Lagrange插值中使用的节点越多，插值多项式的次数就越高。我们自然关心插值多项式增加时，Ln(x)是否也更加靠近被逼近的函数。龙格(Runge)给出的一个例子是极著名并富有启发性的。-Considered at a fixed interval on a function approximation using interpolation. Clearly, Lagrange interpolation nodes are used the more the number of interpolation polynomial higher. We are naturally concerned about the increasing interpolation polynomials, Ln (x) is also closer to being a function approximation. Runge (Runge) give an example of a well-known and are very stimulating.