#include <stdio.h> #include <math.h> // 待求极值的函数,可自己编写 double f(double x) { return pow(x, 3) - 2 * pow(x, 2) + 4; } // 求函数在x处的导数 double df(double x, double h) { return (f(x + h) - f(x - h)) / (2 * h); } // 求函数的极值 double find_extremum(double a, double b, double eps) { double x0, x1, x2, h; x1 = a; x2 = b; h = 0.001; do { x0 = x1; x1 = x2; // 使用牛顿迭代法求解极值点 x2 = x1 - df(x1, h) / ((df(x1, h) - df(x0, h)) / (x1 - x0)); } while (fabs(x2 - x1) >= eps); return x2; } int main() { double a, b, eps; // 获取区间和精度 printf("请输入区间[a, b]和精度eps:\n"); scanf("%lf %lf %lf", &a, &b, &eps); // 调用函数求解 double x = find_extremum(a, b, eps); printf("函数的极值点为:%lf\n", x); printf("函数的极值为:%lf\n", f(x)); return 0; }可以计算三角函数的样例吗
时间: 2024-01-20 13:03:03 浏览: 35
这个代码是用来求解一个函数的极值的,不是用来计算三角函数的。如果你需要计算三角函数,可以使用 math.h 库中的函数,例如 sin、cos、tan 等。以下是一个计算正弦函数的例子:
```
#include <stdio.h>
#include <math.h>
int main() {
double x = 1.0;
double result = sin(x);
printf("sin(%lf) = %lf\n", x, result);
return 0;
}
```
这个程序将输出 "sin(1.000000) = 0.841471"。
相关问题
#include <stdio.h> #include <math.h> // 待求极值的函数 double f(double x) { return pow(x, 3) - 2 * pow(x, 2) + 3 * x - 1; } // 求函数在x处的导数 double df(double x, double h) { return (f(x + h) - f(x - h)) / (2 * h); } // 求函数的极值 double find_extremum(double a, double b, double eps) { double x0, x1, x2, h; x1 = a; x2 = b; h = 0.001; do { x0 = x1; x1 = x2; x2 = x1 - df(x1, h) / ((df(x1, h) - df(x0, h)) / (x1 - x0)); } while (fabs(x2 - x1) >= eps); return x2; } int main() { double a, b, eps; printf("请输入区间[a, b]和精度eps:\n"); scanf("%lf %lf %lf", &a, &b, &eps); double x = find_extremum(a, b, eps); printf("函数的极值点为:%lf\n", x); printf("函数的极值为:%lf\n", f(x)); return 0; }加注释
```c
#include <stdio.h>
#include <math.h>
// 待求极值的函数
double f(double x) {
return pow(x, 3) - 2 * pow(x, 2) + 3 * x - 1;
}
// 求函数在x处的导数
double df(double x, double h) {
return (f(x + h) - f(x - h)) / (2 * h);
}
// 求函数的极值
double find_extremum(double a, double b, double eps) {
double x0, x1, x2, h;
x1 = a;
x2 = b;
h = 0.001;
do {
x0 = x1;
x1 = x2;
// 使用牛顿迭代法求解极值点
x2 = x1 - df(x1, h) / ((df(x1, h) - df(x0, h)) / (x1 - x0));
} while (fabs(x2 - x1) >= eps);
return x2;
}
int main() {
double a, b, eps;
// 获取区间和精度
printf("请输入区间[a, b]和精度eps:\n");
scanf("%lf %lf %lf", &a, &b, &eps);
// 调用函数求解
double x = find_extremum(a, b, eps);
printf("函数的极值点为:%lf\n", x);
printf("函数的极值为:%lf\n", f(x));
return 0;
}
```
二次插值法求最小值的C语言,二次插值法C语言程序.doc
抱歉,我不能提供文档或文件下载。但是,我可以为您提供二次插值法求最小值的C语言代码示例:
```c
#include <stdio.h>
#include <math.h>
double f(double x) {
// 定义目标函数
return pow(x, 3) - 3 * x + 1;
}
double quad_interpolation(double a, double b, double c) {
// 二次插值法
double fa = f(a), fb = f(b), fc = f(c);
double p = (fa - fb) / (a - b);
double q = (fa - fc) / (a - c);
double r = (fb - fc) / (b - c);
double s = p + q - r;
double t = pow(p - q, 2) + (fa - fb) * (r * (b - c) - s * (a - b)) / (2 * (r - p - q));
return b - (b - c) * t / (2 * (fb - fc + r * (b - c)));
}
double min(double a, double b, double eps) {
// 求最小值
double c, fc;
while (fabs(b - a) > eps) {
c = quad_interpolation(a, b, (a + b) / 2);
fc = f(c);
if (fc < f(b)) {
a = b;
b = c;
} else {
b = c;
}
}
return (a + b) / 2;
}
int main() {
double a = -2, b = 2, eps = 1e-6;
printf("The minimum value of f(x) is %lf\n", f(min(a, b, eps)));
return 0;
}
```
这是一个简单的二次插值法求最小值的代码示例,我们先定义了目标函数 `f(x)`,然后使用二次插值法 `quad_interpolation` 来求出极值点,最后再使用二分法求最小值。