用c++语言写,用牛顿法求函数-pow(sin(x), 6) * tan(1 - x) * exp(30 * x)最小值
时间: 2024-12-15 15:26:40 浏览: 1
在C++中,我们可以使用牛顿法(Newton's Method)来寻找一个函数的局部最小值。牛顿法是一种迭代优化算法,通过不断逼近函数的零点来找到极值。对于给定的函数`f(x) = -pow(sin(x), 6) * tan(1 - x) * exp(30 * x)`,我们首先需要定义函数及其导数,并实现一个牛顿迭代器。
以下是一个简单的牛顿法实现示例:
```cpp
#include <cmath>
#include <iostream>
#include <vector>
// 函数定义
double function(double x) {
return -pow(sin(x), 6) * tan(1 - x) * exp(30 * x);
}
// 导数定义
double derivative(double x) {
double dfunc = -6 * pow(sin(x), 5) * cos(x) * tan(1 - x) * exp(30 * x)
+ pow(sin(x), 6) * sec^2(1 - x) * exp(30 * x) - 30 * pow(sin(x), 6) * tan(1 - x) * exp(30 * x);
return dfunc;
}
// 牛顿法迭代
double newtonMethod(double initial_guess, double tolerance = 1e-6, int max_iterations = 100) {
double x = initial_guess;
for (int i = 0; i < max_iterations && abs(function(x)) > tolerance; ++i) {
x -= function(x) / derivative(x);
}
return x;
}
int main() {
double initialGuess = 0.0; // 初始猜测点,可以根据需要调整
double minValue = newtonMethod(initialGuess);
std::cout << "Minimum value of the function is approximately at x = " << minValue << std::endl;
std::cout << "And the value of the function at that point is: f(" << minValue << ") = " << function(minValue) << std::endl;
//
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