谁有数学函数的计算程序，比如说COS函数是怎么用程序实现的？

Question

一般语言里都是直接调用函数，这些底层的函数是怎么实现的？请提供代码，谢谢。

Answer 1

好好学习数学，就可以实现这个代码！泰勒公式---有趣！
$sin(x)= x-\dfrac{x^3}3!+ \dfrac{x^5}5!-\dfrac{x^7}7!·······$
$sin(x)= 1-\dfrac{x^2}2!+ \dfrac{x^4}4!-\dfrac{x^6}6!·······$
做题的时候就是在复习过去的知识--好醉，好玩！
代码如下过去做的sin和改的cos：
#include
using namespace std;
#define pi 3.1415925
#include
int main()
{
double a=1, b=0, c=0, x,n,s;
cin >> x;
x = (x*pi) / 180;
s = x;
for (n = 3;; n += 2)
{
a = a*(n - 1)*n;
b = -b;
c = pow(x, n) / a;
s = s + b*c;
if (c <= pow(10, -6))
{
cout << "sin(x)=" << x << endl;
cout << "" << endl;
break;
}
}
cout << "原先"<<sin(x) << endl;
return 0;
}

改的cos：
#include
#include
#define pi 3.1415925
using namespace std;
int main()
{
double a = 1, b = 1, c = 0, x, n, s;
cin >> x;
x = (x*pi) / 180;
s = 1;
for (n = 2;; n += 2)
{
a = a*(n - 1)*n;
b = -b;
c = pow(x, n) / a;
s = s + b*c;
if (c <= pow(10, -6))
{
cout << "cos(x)=" << s << endl;
break;
}
}

        cout << "原先" << cos(x) << endl;
        return 0;
    }

附图：