class Esercizio4 {

  public static double funzione(double x) {
      double y= 2*(x*x*x)-4*x+1;

      return y;}


      public static void main (String [] urgs)
  {
    System.out.println(+bisez(4,0,1));
  }
public static double bisez (double d, double a, double b){
   double m = a/b;
    double fa = +funzione(a);
    double fb = +funzione(b);
    double fm = +funzione(m);
  for (int i=1; i<=d; i=i+1) {
    if(fm==0)                           return m;
    if((fa<0 && fm>0)|(fa>0 && fm<0))   return +bisez(d-1,a,m);
    if((fb<0 && fm>0)|(fb>0 && fm<0))   return +bisez(d-1,m,b);}
  return m;
}

}