#include<iostream.h>
#include<math.h>
double Y;
double Newdon(double y[],double t,int n)
{  int m=1,i,k;
   double C[11][11]={};
   double s=y[0],d=1;
   for(i=0;i<n;i++)
     C[0][i]=y[i+1]-y[i];
   for(k=1;k<n;k++)
   {  for(i=0;i<n;i++)
      {  C[k][i]=C[k-1][i+1]-C[k-1][i];
      }
   }
   
   for(i=1;i<=n;i++)
   {  m*=i;
      d*=t-i+1;
      s=s+C[i-1][0]*(double)(d/m);
   }

   Y=s;
}

void main()
{  int i,n=10;
   double t,x=1.98;
   double y[11]={};
   t=(x-1)/0.1;
   for(i=0;i<=n;i++)
   {  y[i]=log(1+i*0.1);}
   Newdon(y,t,n);
   cout<<Y<<endl;

}