#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <locale.h>
int main(void)
{ 
  setlocale(LC_ALL, "Russian");  
    
  const double eps=0.00001;
  double F, x, s, s1=0.0;
  int k=1;
  printf ("Введите X:\n");
  scanf ("%lf", &x);
  s=x;
  F=0;
  do
  {    
  s1=s1+F;
  F=cos(k*x)/k*k;
  s=s+F;
  k++;
  }      
  while (abs(s1-s)>eps);
  printf ("%lf", s);
  
  system("PAUSE");	
  return 0;
}