#include <iostream>
using namespace std;
double Sum(double x, double err)
{
double S = 10.;
double an = 3*x;
for( double n = 2; an > err; n++ )
{
an *= x / n;
S += (2*n+1)*an;
cout<<"\rn = "<<n<<" an = "<<an<<" S = "<<S;
}
cout<<endl;
return S;
}
int main()
{
double x, err;
cout<<"Enter x : ";/*cin>>x; cin.get();*/x = 3;
cout<<"Enter error : ";/*cin>>err;cin.get();*/err = 0.001;
cout<<"Sequence Sum: "<<Sum(x, err)<<endl;
cin.get();
return 0;
}