Xây dựng hàm cos(x)
Code:
#include <bits/stdc++.h>
using namespace std;
int giaithua(int n)
{
if(n == 0)
return 1;
if(n > 0)
{
int j = 1;
for(int i = 1 ; i <= n ; i++)
j = j * i;
return j;
}
}
long double COS(double x)
{
const double eps = pow(10,-6);
long double sum = 0;
for(int i = 0 ; i <= pow(10,9) ; i++)
{
sum = sum + pow(-1,i)*(pow(x,2*i)/giaithua(2*i));
if(abs(pow(-1,i)*(pow(x,2*i)/giaithua(2*i))) < eps)
break;
}
return sum;
}
int main()
{
double x;
cin>>x;
const double PI = 3.14;
cout<<COS((x*PI)/180);
return 0;
}
