首页已知函数表如下： x 0.4 0.55 0.8 0.9 1 y 0.41075 0.57515 0.88811 1.02652 1.17520 请写出用拉格朗日插值多项式函数值的c语言和c++代码

已知函数表如下： x 0.4 0.55 0.8 0.9 1 y 0.41075 0.57515 0.88811 1.02652 1.17520 请写出用拉格朗日插值多项式函数值的c语言和c++代码

时间: 2024-02-14 09:08:45 浏览: 138

以下是用拉格朗日插值多项式求解函数值的C语言代码： ```c #include <stdio.h> double lagrange_interpolation(double x[], double y[], int n, double xi); int main() { double x[] = {0.4, 0.55, 0.8, 0.9, 1}; double y[] = {0.41075, 0.57515, 0.88811, 1.02652, 1.17520}; double xi = 0.6; double yi = lagrange_interpolation(x, y, 5, xi); printf("f(%lf) = %lf\n", xi, yi); return 0; } double lagrange_interpolation(double x[], double y[], int n, double xi) { double result = 0; for (int i = 0; i < n; i++) { double term = y[i]; for (int j = 0; j < n; j++) { if (j != i) { term *= (xi - x[j]) / (x[i] - x[j]); } } result += term; } return result; } ``` 以下是用拉格朗日插值多项式求解函数值的C++代码： ```c++ #include <iostream> using namespace std; double lagrange_interpolation(double x[], double y[], int n, double xi); int main() { double x[] = {0.4, 0.55, 0.8, 0.9, 1}; double y[] = {0.41075, 0.57515, 0.88811, 1.02652, 1.17520}; double xi = 0.6; double yi = lagrange_interpolation(x, y, 5, xi); cout << "f(" << xi << ") = " << yi << endl; return 0; } double lagrange_interpolation(double x[], double y[], int n, double xi) { double result = 0; for (int i = 0; i < n; i++) { double term = y[i]; for (int j = 0; j < n; j++) { if (j != i) { term *= (xi - x[j]) / (x[i] - x[j]); } } result += term; } return result; } ```

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