#include<iostream.h>
#include<conio.h>
#include<math.h>
int main()
{ float x,t,sum;
int i,n=20;
cout<<"Input X : \n";
cin>>x;
x=x*3.1412/180;
t=t+1;
sum=1;
for(i=1;i<=n;++i)
{ t=t*pow((double)(-1),(double)(2*i-1))*x*x/(2*i*(2*i-1));
sum +=t;
}
cout<<"cos(X) ="<<sum<<"\n";
system ("pause");
return 0;
}
