#include <iostream>
#include <math.h>

using namespace std;

double
f (double x)
{
  return sin (x) * x * x + exp (-x);
//  return cos(x)*x*x+1/log(2.0+x*x);
}

double
fp (double x)
{
  return cos (x) * x * x + 2 * sin (x) * x - exp (-x);
//  return -sin(x)*x*x+2.0*cos(x)*x-2.0/pow(log(2.0+x*x),2.0)*x/(2.0+x*x);

}

double
opt (double x1, double x2, double x3, double y1, double y2, double y3)
{
  return
    (x3 * x3 * (y1 - y2) + x1 * x1 * (y2 - y3) +
     x2 * x2 * (y3 - y1)) / (2.0 * (x3 * (y1 - y2) + x1 * (y2 - y3) +
				    x2 * (y3 - y1)));
}

main ()
{
  const double tol = pow (10.0, -6.0);
  double x = -1.5;
  double xold;
  double x1, x2, x3;
  double a1, a2, a3;

  cout << x << "\t" << f (x) << "\n";

  while (1) {
    double ngrad = -fp (x);
    if (ngrad == 0.0)
      break;
    a1 = 1;
    while (f (x + a1 * ngrad) > f (x) and fabs (a1 * ngrad) > tol) {
      a1 /= 2.0;
    }
    x1 = x + a1 * ngrad;
    a2 = a1 / 2.0;
    x2 = x + a2 * ngrad;
    a3 = opt (0, a1, a2, f (x), f (x1), f (x2));
    x3 = x + a3 * ngrad;
    xold = x;
    if (f (x3) < f (x1))
      x = x3;
    else
      x = x1;
//    cout << x << "\t" << f(x) << "\n";
    cout << x << "\t" << f (x) << "\t" << xold << "\t" << x1 << "\t" << x2 <<
      "\t" << x3 << "\n";
    if (fabs (xold - x) < tol)
      break;
  }
}