说明：  插值在离散数据的基础上补插连续函数，使得这条连续曲线通过全部给定的离散数据点。插值是离散函数逼近的重要方法，利用它可通过函数在有限个点处的取值状况，估算
(Interpolation is based on the discrete data to supplement the continuous function, so that the continuous curve passes through all the given discrete data points. Interpolation is an important approach to discrete function approximation. It can be used to estimate the value of a function at a finite number of points.)