依次用n=8的复化梯形公式、n=4的复化辛普森公式计算定积分∫sinx/xdx从0到1用c语言代码实现

复化梯形公式的C语言代码如下：

#include <stdio.h>
#include <math.h>

double f(double x) {
    return sin(x) / x;
}

double trapezoidal(double a, double b, int n) {
    double h = (b-a)/n;
    double sum = 0.5*(f(a) + f(b));
    for (int i = 1; i < n; i++) {
        double x = a + i*h;
        sum += f(x);
    }
    return h*sum;
}

int main() {
    double a = 0.0, b = 1.0;
    int n = 8;
    double result = trapezoidal(a, b, n);
    printf("The result is: %lf\n", result);
    return 0;
}

复化辛普森公式的C语言代码如下：

#include <stdio.h>
#include <math.h>

double f(double x) {
    return sin(x) / x;
}

double simpson(double a, double b, int n) {
    double h = (b-a)/n;
    double sum = f(a) + f(b);
    for (int i = 1; i < n; i += 2) {
        double x = a + i*h;
        sum += 4*f(x);
    }
    for (int i = 2; i < n-1; i += 2) {
        double x = a + i*h;
        sum += 2*f(x);
    }
    return (h/3)*sum;
}

int main() {
    double a = 0.0, b = 1.0;
    int n = 4;
    double result = simpson(a, b, n);
    printf("The result is: %lf\n", result);
    return 0;
}